uhJi %1'i;;. HARVARD UNIVERSITY LIBRARY OF THE Museum of Comparative Zoology 5_^4-Z. University of Kansas Publications museum of natural history VOLUME 8 • 1954-1956 EDITORS E. Raymond Hall, Chairman A. Byron Leonard Robert W. Wilson Museum of Natural History UNIVERSITY OF KANSAS LAWRENCE ^ 1956 Museum of Natural History university of kansas lawrence m- iz^v JP.H i\ \957 mm. PRINTED BY FERD VOILAND. JR . STATE PRINTER TOPEKA. KANSAS I9S6 26-5803 CONTElSfTS OF VoLUME 8 CONTENTS 1. Life history and ecology of the five-Hned sldnk, Eiimeces fasciatus. By Henry S. Fitch. Pp. 1-156, pis. 1-2, 26 figs, in text, 17 tables. September 1, 1954. 2. Myology and serology of the Avian Family Fringillidae, a taxonomic study. By William B. Stallcup. Pp. 157-211, 23 figs, in text, 4 tables. November 15, 1954. 3. An ecological study of the collared lizard (Crotaphytus collaris). By Henry S. Fitch. Pp. 213-274, pis. 3-6, 10 figs, in text, 9 tables. February 10, 1956. 4. A field study of the Kansas ant-eating frog, Gastrophryne olivacea. By Henry S. Fitch. Pp. 275-306, 9 figs, in text. February 10, 1956. 5. Check-Ust of the birds of Kansas. By Harrison B. Tordoff. Pp. 307-359, 1 fig. in text. March 10, 1956. 6. A population studv of the prairie vole (Microtus ochrogaster) in north- eastern Kansas. By Edwin P. Martin. Pp. 361-416, 19 figs, in text. April 2, 1956. 7. Temperature responses in free-living amphibians and reptiles of northeast- em Kansas. By Henry S. Fitch. Pp. 417-476, 10 figs, in text, 6 tables. June 1, 1956. 8. Food of the crow, Corvus brachyrhynchos Brehm, in south-central Kansas. By Dwight Piatt. Pp. 477-498, 4 tables. June 8, 1956. 9. Ecological observations on the woodrat, Neotoma floridana. By Henry S. Fitch and Dennis G. Rainey. Pp. 499-533, 3 figs, in text. June 12, 1956. 10. Eastern woodrat, Neotoma floridana: Life history and ecology. By Den- nis G. Rainey. Pp. 535-646, 12 plates, 13 figs, in text. August 15, 1956. Index. Pp. 647-675. D M Pi- ^L J Y University of Kansas Publications Museum of Natural History Volume 8, No. 1, pp. 1-156, 2 pis., 26 figs, in text, 17 tables September 1, 1954 ^^ Life History and Ecology of the Five-lined Skink, Eumeces fasciatus BY HENRY S. FITCH PV 2 3 -M ^ blutfArU^ul I University of Kansas Lawrence 1954 UNIVERSITY OF KANSAS PUBLICATIONS, MUSEUM OF NATURAL HISTORY Institutional libraries interested in publications exchange may obtain this series by addressing the Exchange Librarian, University of Kansas Library, Lawrence, Kansas. Copies for individuals, persons working in a particular field of study, may be obtained by addressing instead the Musemn of Natural History, University of Kansas, Lawrence, Kansas. There is no provision for sale of this series by the University Library which meets institutional requests, or by the Museum of Natural History which meets the requests of individuals. However, when individuals request copies from the Museum, 25 cents should be included, for each separate number that is 100 pages or more in length, for the purpose of defraying the costs of vvaapping and mailing. * An asterisk designates those numbers of which the Museum's supply (not the Li- brary's supply) is exhausted. Numbers published to date, in this series, are as follows: Vol. 1. 1. The pocket gophers (Genus Thomomys) of Utah. By Stephen D. Duirant. Pp. 1-82, 1 figure in text. August 15, 1946. 2. The systematic status of Eumeces pluvialis Cope, and noteworthy records of other amphibians and reptiles from Kansas and Oklahoma. By Hobart M. Smith. Pp. 85-89. August 15, 1946. 3. The tadpoles of Bufo cognatus Say. By Hobart M. Smith. Pp. 93-96, 1 figure in text. August 15, 1946. 4. Hybridization between two species of garter snakes. By Hobart M. Smith. Pp. 97-100. August 15, 1946. 5. Selected records of reptiles and amphibians from Kansas. By John Breukel- man and Hobart M. Smith. Pp. 101-112. August 15, 1946. 6. Kyphosis and other variations in soft-shelled turtles. By Hobart M. Smith. Pp. 117-124, 3 figures in text. July 7, 19^7. *7. Natural history of the prairie vole (Mammalian Genus Microtus). By E. W. Jameson, Jr. Pp. 125-151, 4 figures in text. October 6, 1947. 8. The postnatal development of two broods of great homed owls (Bubo vir- ginianus). By Donald F. Hoffmeister and Henry W. Setzer. Pp. 157-173, 5 figmres in text. October 6, 1947. 9. Additions to the list of the birds of Louisiana. By George H. Lowery, Jr. Pp. 177-192. November 7, 1947. 10. A check-list of the birds of Idaho. By M. Dale Arvey. Pp. 193-216. No- vember 29, 1947. 11. Subspeciation in pocket gophers of Kansas. By Bernardo Villa-R. and E. Raymond Hall. Pp. 217-236, 2 figures in text. November 29, 1947. 12. A new bat (Genus Myotis) from Mexico. By Walter W. Dalquest and E. Raymond Hall. Pp. 237-244, 6 figures in text. December 10. 1947. 13. Tadarida femorosacca (Merriam) in Tamaulipas, Mexico. By Walter W. Dalquest and E. Raymond Hall. Pp. 245-248, 1 figure in text. December 10. 1947. 14. A new pocket gopher ( Thomomys ) and a new spiny pocket mouse (Liomys) from Michoacdn, Mexico. By E. Raymond Hall and Bernardo Villa R. Pp. 249-256, 6 figures in text. July 26, 1948. 15. A new hyUd frog from eastern Mexico. By Edward H. Taylor. Pp. 257- 264, 1 figure in text. August 16, 1948. 16. A new extinct emydid turtle from the Lower Pliocene of Oklahoma. By Edwin C. Galbreath. Pp. 265-280, 1 plate. August 16, 1948. 17. Pliocene and Pleistocene records of fossil turtles from western Kansas and Oklahoma. By Edwin C. Galbreath. Pp. 281-284. August 16. 1948. 18. A new species of heteromyid rodent from the Middle Oligocene of north- eastern Colorado with remarks on the skull. By Edwin C. Galbreath. Pp. 285-300, 2 plates. August 16, 1948. 19. Speciation in the Brazilian spiny rats (Genus Proechimys, Family Echi- myidae). By Joao Moojen. Pp. 801-406, 140 figures in text. December 10, 1948. 20. Three new beavers from Utah. By Stephen D. Durrant and Harold S. Crane. Pp. 407-417, 7 figures in text. December 24, 1948. 21. Two new meadow mice from Michoac&n, Mexico. By E. Raymond Hall. Pp. 423-427, 6 figures in text. December 24. 1948. 22. An annotated check list of the mammals of Michoac4n, Mexico. By E. Ray- mond Hall and Bernardo Villa R. Pp. 431-472, 2 plates, 1 figure in text. December 27. 1949. 23. Subspeciation in the kangaroo rat, Dipodomys ordil. By Henry W. Setzer. Pp. 473-573, 27 figures in text, 7 tables, December 27. 1949. (Continued on inside of bacic cover) blU' 111 «K« ■ NOV 2 3 1954 University of Kansas Publications Museum of Natural History Volume 8, No. 1, pp. 1-156, 2 pis., 26 figs, in text, 17 tables September 1, 1954 Life History and Ecology of the Five-lined Skink, Eumeces fasciatus BY HENRY S. FITCH University of Kansas Lawrence 1954 Untversity of Kansas PtrBLiCAXioNS, Museum of Natural History Editors: E. Ra>'mond Hall, Chairman, A. Byron Leonard, Robert W. Wilson Volume 8, No. 1, pp. 1-156, 2 pis., 26 figs, in text, 17 tables Published September 1, 1954 University of Kansas Lawrence, Kansas PRINTED BY FERD VOILAND. JR., STATE PRINTER TOPEKA. KANSAS 1954 25-3559 LIFE HISTORY AND ECOLOGY OF THE FIVE-LINED SKINK, EUMECES FASCIATUS By Henry S. Fitch Introduction The common five-hned skink (or common blue-tailed skink) is a small woodland lizard, abundantly and widely distributed over the eastern United States. Many authors have casually discussed this lizard or have treated in detail some phase of its biology. Excellent brief summaries of the known facts concerning its life history have been published by Smith (1946:349-350 and 1950:187-188) and Pope (1947:153-157). Nevertheless, no thoroughgoing study of its life history and ecology has heretofore been made. In 1932, taxonomic studies by Dr. Edward H. Taylor revealed that the lizards previously referred to in the literature as Eumeces fasciatiis, actually were three closely related and similar, partly sympatric species. Although Taylor's work was careful and de- tailed, and indicated numerous minor differences by which the three species could be distinguished, many herpetologists were reluctant to accept his findings for nearly a decade thereafter. Consequently a large amount of literature concerning five-hned skinks is either obviously composite in the sense that it is based upon two or three species, or is not definitely assignable to any one species. In the study here reported upon, all pertinent literature available to me has been examined, and evaluated, and important findings of other authors have been incorporated in the discussion. However, mine was primarily a field study, and in one small part of the geographic range of the one species. The University of Kansas Natural History Reservation is a tract of 590 acres preserved as a natural area, available for the pursuit of ecological studies. The studies undertaken include intensive investigations of selected species of vertebrate animals. The main criteria used in selecting these species have been whether or not they were sufficiently abundant and generally enough distributed to play an important role in the over-all ecology of the area, and whether a species was sufficiently accessible for study with available techniques. Among the 300 species of vertebrate animals recorded (3) 4 University of Kansas Publs., Mus. Nat. Hist. from the Reservation, the fi\'e-hned skink is one of those most frequently noticed in the field. In actual numbers it is probably exceeded only by the cricket frog (Acris grijUus), the leopard frog {Rana pipiens), the ring-necked snake {Diadophis punctatus), the prairie vole ( Microtus ochrogaster) and perhaps the white-footed mouse (Peromyscus leucopus). Although numerous, the skink is not easy to study because it is secretive in its behavior, and is in- active in inaccessible shelters during the greater part of the year. The five-lined skink generally occurs along with a characteristic set of community associates in a particular type of situation. It is a predator on various small animals, mostly invertebrates. For some of the many prey species the effect is certainly negligible, but for others its predation may be a major ecological factor. In areas where optimum habitat conditions exist its biomass may exceed that of any other insectivorous animal, and in such situations it assumes a major role as a predator and as a competitor with other insectivorous types. In turn it provides part of the food source of various larger predators, including reptiles, birds and mammals. It is a host and carrier of various parasites, including at least one species that regularly attacks humans — the common chigger. It is not evident on the basis of the present findings that the skink is either harmful or beneficial to any perceptible degree, in its over-all effect on human affairs and economy. Nevertheless, there probably are various unsuspected relationships. In the course of my field study many workers on the University of Kansas Natural History Reservation helped by capturing skinks; especially Sydney Anderson, Richard Freiburg, John Hawken, Den- nis G. Rainey and Lewis L. Sandidge. Mr. Robert Gordon very kindly furnished information on specimens in the Tulane Univer- sity collection, which served as a basis for comparing the breeding schedule of the southern population with that of E. fasciatus in northeastern Kansas. Dr. W. J. Breckenridge kindly permitted examination of material in the University of Minnesota Museum of Natural History. Dr. Edward H. Taylor has made helpful sugges- tions from time to time. Mr. Richard B. Loomis helped me in various ways with the field work, and made available his personal field notes with records of predation on Eumeces by various snakes. Dr. E. Raymond Hall, Director of the Museum of Natural History, has critically examined the manuscript, and has been helpful in various ways. The line drawings and graphs, with the exception of Figures 8 and 9, were made or completed by Mrs. Louise Brunk, artist for the Museum. Life History and Ecology of Five-lined Skink 5 The study here reported on was initiated in May 1949, and was continued through 1950, 1951 and 1952. A few observations made in 1948 have been included. Various separate items of information obtained in 1953 have hkewise been incorporated especially where histories of individual skinks are presented, but the manuscript was completed in essentially its present form in the fall of 1952. Methods Skinks were obtained by active search; rocks and boulders were lifted up and the skinks thus exposed were seized by hand before they had time to escape. This method was ejffective when the skinks were using rocks for shelter and when temperatures were low enough so that they were slow and sluggish, but in hot weather the skinks were so quick and active that those exposed usually es- caped. Usually skinks could be obtained much more easily by trapping. At the pond rock pile ( Fig. 26 ) , for instance, shelter was so readily available that the skinks could seldom be caught by hand. Gallon cans buried with the tops open flush with the surface of the ground served as pitfalls and were effective when they were carefully placed, at the bases of rock ledges or logs or stumps, where the skinks were most likely to fall into them. Most of the skinks recorded at the rock pile were caught by this method, and some- times several were caught together in the same pitfall. Ordinarily each pitfall was covered with a large flat rock, propped against a nearby object to leave ample space for the skink to enter beneath it. The rocks provided protection from direct sunlight, from rain, and from predators. Still another method of catching skinks was with wire screen funnel traps (Fitch 1951:77). These funnel traps were of different sizes, and were made of different kinds of wire mesh. They were set for reptiles that were mostly larger than five- lined skinks, and those having quarter-inch wire mesh permitted many of the immature skinks to escape. Most of these funnel traps were from about one foot long and five inches in diameter, to about twice these dimensions, with funnel openings about 1.5 inches in diameter. Some made of /s inch wire mesh, six or seven inches long, and three or four inches in diameter, with funnel openings only a httle larger than the body diameter of an adult skink, were found to be suitable for skinks of all sizes, and were used success- fully at the pond rock pile. Most of the skinks trapped were adult males, and they were taken chiefly in May. The funnel traps were generally placed at the edges of rock outcrops, boulders or logs, where skinks were likely to be intercepted in their usual travel 6 UNivERsrri' of Kansas Publs., Mus. Nat. Hist. routes. Each method of collecting skinks resulted in occasional mortalit)- to tliem but most losses were in those caught in funnel traps. In these traps they sustained rapid loss of moisture, and were usually somewhat desiccated. Two or more adult males were often caught together, and in most of these instances the first one caught probably served as bait attracting another and arousing his pugnacious interest. Injuries were frequent, and some deaths oc- curred because in the close confines of a trap the loser in a fight was unable to escape further attacks. Most of the skinks caught were examined, and released within a few minutes. Snout-vent length was measured by holding the skink against a rigid transparent plastic millimeter ruler and exert- ing a slight pull on each end of the lizard until it tired and relaxed its muscles, eliminating bends and kinks. Even with such pre- caution, precise measurements could not be obtained and the read- ings often varied a milHmeter or more for the same skink measured two or more times on the same day. Tail length was similarly re- corded with separate readings for the original and regenerated portions. Also recorded were sex (when discernible), color and pattern, breeding data, injuries, general condition, and sometimes temperature. Many of the skinks were brought to the laboratory, and were weighed to the nearest tenth of a gram. Occasional trips were made to localities away from the Reserva- tion to collect skinks. Some of those obtained were kept under observation in terraria where their behavior was studied. Most were preserved and were used for data on habitat preferences, seasonal changes in the gonads, size group, stomach contents, and various other items of information. Description The scutellation and osteology have been described in detail by Taylor (1936:39-48 and 199-206) and others, and need not be re- peated. The five-lined skink is slender and elongate, somewhat snakelike (though much less so than many other skinks) as the head, neck, body, and tail are not well set off from each other, and the sleek, streamlined contours are broken only by the small limbs pro- truding from the sides of the body. The body is slightly flattened laterally, tending toward quadrangular shape in cross section. The head is wedge-shaped, with a short, rounded snout. The nostrils are laterally placed, well back from the tip of the snout. The eyes are small and deep set; the iris is dark. The neck is thick and strong, nearly as long as the head. The torso is SM to 4 times as long as it is wide. The tail is almost square in cross section at its base, but Life History and Ecology of Five-lined Skink 7 is circular in cross section for most of its length. The limbs are moderately developed; when adpressed along the sides of the body, the forelimb and hind limb overlap by a length about equal to the longest toes of the forelimb. The limbs are pentadactyl and all the toes are well developed and have claws (Figures 1 and 2). The claws are short, and are curved in such a manner that their tips are directed downward, each approximately at right angles to the axis of the toe (Figure 2b). The limbs are moderately thick and muscular. The upper arm and forearm segments are of approxi- mately equal length, as are the femoral and tibio-fibular segments of the hind limb. Fig. 1. Antipalmar view of right front foot, X 9. Fig. 2. B A. Antiplantar view of right hind foot, X 9. B. Terminal part of second toe of left hind foot, and its claw, in lateral view, X 9. 8 University of Kansas Publs., Mus. Nat. Hist. The five-lined pattern is characteristic of the hatchhng, but gradual ontogenetic change results in its dulling, suppression, and eventual loss. In the hatchling the ground color of the head and body is black or dark brown, with five milky white longitudinal stripes extending the length of the head and body, and on the basal one-fourth of the tail. The five light lines are of approximately equal width, and are separated by dark interspaces VA to 2 times as wide. The mid-dorsal stripe includes most of the two mid-dorsal scale rows. Posteriorly it extends onto the base of the tail, where it be- comes increasingly suffused with the blue color of the tail, widens, and loses its identity. In the nuchal region, this dorsal stripe nar- rows and splits into left and right branches, which diverge anteriorly to form a lyrate pattern on the head. On either side of the dorsal stripe are the dark interspaces, nearly twice as wide as the stripe itself and tapering to a point posteriorly on the tail, likewise taper- ing anteriorly to a point immediately above and in front of the eye. Lateral to these dark areas are the dorsolateral stripes; they extend from the basal one-fourth of the tail anteriorly onto the head along the superciliary region, tapering to a point on the anterior super- ciliary. Below these stripes are the dark lateral areas which extend from the basal part of the tail anteriorly along the sides of body and neck region (including the upper half of the aperture of the ear), eye region, and loreal region. Below this dark area on each side is the lateral stripe. It extends along the sides just above the level of the limb insertions ( broken or pinched to a fraction of its average width above the hind limb insertion), broken by the ear opening, and extending anteriorly to include all the supralabial scales (with the exception of their upper edges) and the rostral. Here the left and right lateral stripes may be said to join; however in the facial region these stripes are not well defined, partly because the dark areas that border their lower edges do not extend so far forward. This lowermost dark area is about equal in width to the lateral stripe. It extends from the posterior infralabials posteriorly, to include the fore- and hind-limbs, and onto the basal part of the tail. The ventral surface of the head and body is dull white or pearly gray. Thus, there are 12 longitudinal bands of color on the body: the five narrow, subcqual, pale lines separated by the six dark areas, of which the dorsal and dorsolateral are broad and of approximately equal width, while the ventrolateral is narrower; and lastly the broad, pale ventral area. The tail in young individuals is bright blue. In Eumeces the tail characteristically has a color different from that of the body, and is Life History and Ecology of Five-lined Skink 9 usually more conspicuous; in many species it is blue, but in others it may be purple, greenish-blue, red, pink, or orange. Hatchlings have the most brightly colored tails, and as growth proceeds the colors gradually become duller. In E. fasciatus the bright colors of the tail are mostly or entirely lost in old adults, especially in males, and in individuals of either sex that have lost their original tails B Fig. 3. A. B. C. D. Osteoderm of an old adult male, from near the midline of the back, X25. Another osteoderm from same male, from belly near midline, X 25. Another osteoderm from side of same male, at a point approxi- mately halfway between foreleg and hind leg, X 25. Osteoderm of a juvenile obtained in April, from near midline of back, X 25. Tongue from dorsal view, shown in its normal position in the lower jaw, X 2%. 10 University of Kansas Publs., Mus. Nat. Hist. and regenerated new tails. Young which lose their tails and regen- erate them at an early age have the regenerated portions colored al- most as brightly as the originals at first. The skin is tight fitting and relatively thick, stiflFened by a bony armor. A small bony plate or osteoderm underlies each scale. Oliver (1951:127) has called attention to the pattern of ornamenta- tion on the osteoderms, which becomes more complex with advanc- ing age. He has suggested the possibility that age might be accu- rately determined on the basis of extent of osteodermal ornamenta- tion. I have compared osteodermal ornamentation in marked individuals of known age, but have found it to be of limited applica- bility as a method of age determination; size and pattern are prob- ably more satisfactory bases for estimating age, even though they do not permit definite aging of old adults and are not infallible for skinks short of adult size. In adult E. fasciatus the pattern of ornamentation is closely similar to that figured for E. Jaticeps by Oliver (op. cit. ) and also resembles the pattern shown for an Old World skink, Mahinja midtifasciata, as figured by Smith (1935:2). The pattern differs somewhat in osteoderms on different parts of the body, and is most nearly symmetrical in those near the mid-line on either dorsal or ventral surface ( Figure 3 ) . Relationships Eumeces is a widespread genus occurring in the New World in southern Canada and southward into Costa Rica. The greatest number of forms is in Mexico. In the Old World numerous species occur in southeastern Asia and on adjacent islands, and other spe- cies occur westward across southern Asia, and across North Africa to Morocco, with a major break in the continuity of distribution in the Himalayan region. Taylor in his revision recognized 57 forms with fifty full species, belonging to 15 major groups within the genus. Since then only relatively minor changes in classification have been proposed. Several new species and subspecies have been named, and several species have been relegated to the status of subspecies. Within the genus there are several groups that have representa- tives in both the New World and the Old World. Smith and Ethe- ridge (1953:159) point out that the most primitive line of Eumeces is best represented in the Old World, where there are two groups and nine species, while in the New World this line has only tliree tropical relict forms. For this reason. Smith and Etheridge concur with Taylor (1936:67) in considering the genus to be of Old World Life History and Ecology of Five-lined Skink 11 origin; but the two main lines of the genus (the four-lined and five- lined stocks ) are both regarded as being of New World origin. Ac- cording to this idea, the Asiatic members of these two groups mi- grated from the New World. In the early Tertiary, warm temperate climates extended north to the Arctic Circle, and Eumeces, or at least some of its species, may have had a distribution straddling migration routes to both North America and Asia. Of the 15 groups within the genus, the fasciatus group, with a dozen species, has more representatives than any other. The fasciatus group is characterized by having the tail bright blue with dorsal body pattern of five light lines on a darker ground color; mid- dorsal line bifurcating on head to form lyrate markings ( this striped pattern and bright color of the tail becoming dull or obsolete in the adults); medial preanal scales overlapped by those lateral to them; two pairs of nuchals; no postfemoral pocket; four supraocu- lars; scales on sides of body in parallel rows. The characters that separate members of the fasciatus group from each other are minor. The width and position of the light lines differ somewhat among them. The mid-dorsal light line bifurcates either on tlie nuchals or on the parietals. The complex of scales in the temporal region differ in shape and relative size. The following table, compiled mostly from information set forth by Taylor (1936:186-283), indicates some of the main differences and similarities between species in the chief characters upon which the classification is based. The close resemblance between E. fasciatus and its Asiatic rela- tives is remarkable considering the great distance separating them and the long time that must have elapsed since their isolation be- gan. Some of the Asiatic forms differ from each other almost as much as they differ from fasciatus. Of the Asiatic species, elegans, tamdaoensis, oshimensis, and marginatus differ from fasciatus in markedly larger size; elegans, marginatus, oshimensis, and stim- sonii differ in lacking a postnasal; all but tamdaoensis tunganus and xanthi differ in having only a single postmental; all but tunganus, E. latiscutatus okadae (and sometimes oshimensis and elegans) differ in reduced number of scale rows; all but tunganus differ in having a lateral postanal scale differentiated, and usually keeled; tunganus, xanthi and elegans differ in having a patch of enlarged scales on the posterior side of the thigh; and in all, the primary temporals and upper and lower secondary temporals differ in size and proportions. Although some of the Asiatic forms seem to be directly derived from others, fasciatus is somewhat intermediate 12 UNR'ERsrri' OF Kansas Publs., Mus. Nat. Hist. 03 U o en III o Id O o I u en crt w o c'—' 43 3 T3 ■t» c snjTy}nosi}Tyi rtS TS u O to ^ 3 o u « J2 ^ 3 iC-JS oc a »-4 OS ^H C^ _:r: fe 1 I', unoquvq C c3 i 3 tn 3 «c u (N *-> <; 03 CC '^ (N c3 fe '■^■S^ .(^ 13 is 0) 3 c 4J-3 iiuostuiis M^-3 T3 CO a; EP3 C CO ^ rt ^H CO ^ g-5 1 • -a ■»j . ■1-3 QJ sisuaiuiyso is 3 o: J2 OC 5: 3 u 55 3 12 ^^Sd iC ',3 CR 03 »-H (N ^ c3 S 8tSU90T>piUDJ ^1 t3 3 IC3: -k3 3 en > oj OC 1 : ^y inu3 « ) a. c ^:2 m ►OS « ) a c<) 0" 03 3 (£ »<-( . tn iT3 t^_ 3 I £ ^ 3 c^ ! .11 ! 1° ' 3 h f : eS 8:S m c _o ■*3 3 _^ *c CD Q 1 1 ■S.S <5 ' 1 ' 1 1 0. 2 t a c 5 -^ ; Is Median subcaudal Life History and Ecology of Five-lined Skink 13 between the more divergent forms, and fulfills most of the condi- tions to be looked for in an ancestral type. The American Eumeces laticeps and E. inexpectatus seem to be more specialized than E. fasciatus and might have been derived from it or from a common ancestor differing but httle from the modern fasciatus. Both differ from fasciatus in having more scale rows. E. laticeps also differs in having eight instead of seven supra- labials and in having the median subcaudal scales greatly widened, in having intercalated plates on the outer side of the fourth toe nearly to the ultimate phalanx, posterior supralabial low and elongate, young sometimes seven-lined instead of five-lined, and especially in much larger size, stocky build, and in early loss of striped pattern. E. inexpectatus differs in having the median sub- caudals not at all enlarged, and in having the dorsolateral stripes a little more widely separated from the mid-line. Eumeces fasciatus and its relatives present a curious exception to Jordan's Rule, which states that the nearest relatives of any given species are to be found neither in the same area nor in a remote one, but in an adjacent region separated by a barrier. E. fasciatus is absent from almost all of Florida; otherwise its range overlaps most of the ranges of both laticeps and inexpectatus, the former including the southeastern United States south of about latitude 40°, and the latter being mainly in the Atlantic and Gulf states from Chesapeake Bay into eastern Louisiana. Presumably both of these species began their differentiation as southern populations of an ancestral fasciatus and later became isolated from it and continued their differentiation until they overlapped it again as distinct species. The differentiation of laticeps, being much greater, pre- sumably took place at an earlier time than did that of inexpectatus, and at present it overlaps fasciatus more extensively. E. laticeps probably diverged to such an extent that competition with fasciatus is greatly reduced where the two species occur together. Since Eumeces laticeps was recognized by Taylor as a species distinct from fasciatus, numerous authors have accumulated field observations that demonstrate ecological divergence between the two. Conant (1951:33) wrote that in Ohio laticeps prefers a dry habitat of bare rocks, cliffs, dry hillsides, and trees. He summed up the habitat difference as follows: "Fasciatus appears to be essen- tially terrestrial, to prefer a moist environment and to be at home in ravines in southern Ohio. Laticeps on the other hand, is largely arboreal (particularly adults), prefers dry cliffs, sunny hillsides and hilltops and lives in general above the habitat of fasciatus." Netting 14 Univ'ersity of Kansas Publs., Mus. Nat. Hist. (1939:127) likewise states that in Pennsylvania E. laticeps inhabits drier places than does fasciatiis, and is largely arboreal. Other authors with few exceptions agree that laticeps is largely arboreal, but most describe it as at home in forest swamps and bottomlands. My own field experience with it is limited. In the Pigeon Lake area of Miami County, Kansas, the northwesternmost known locality of occurrence for laticeps, the habitat relations described by Conant for Ohio were almost reversed. Eumeces laticeps was relatively scarce, and confined to the vicinity of the swamp chiefly in areas that are flooded in time of high water. All those seen were on or near massive snags of dead trees still standing, but decayed and honeycombed with cavities. Slabs of bark clinging loosely to the tree trunks, with spaces beneath, provided shelter for the skinks and for the abundant arthropod fauna which probably constituted their chief food source. This is one of the few places in Kansas where a remnant of the original bottomland forest remains. In central Louisiana, in 1947 and 1948, persons living on the Kisatchie National Forest told me of large, red-headed skinks living in hollow trees, which must have been £. laticeps. In the literature E. laticeps is frequently referred to as red-headed, although the reddish suffusion on the head of the adult male is ephemeral in this species as it is in E. fasciatus and others. The heightened activity of the adult males in the breeding season seems to have drawn attention to this con- spicuous temporary coloration while its absence at other seasons has scarcely been mentioned. Mansueti (1948:213) describing the habits of laticeps in Mary- land, Louisiana and elsewhere in the southern states, emphasizes its arboreal habits, referring to it as " 'scorpion' of the treetops." He describes it as dashing up and down tree trunks, along fences, and in abandoned buildings. However, he states that it also spends much time on the ground, and may take refuge in holes and cracks near ground level, and gravid females are less arboreal, making their nests in decayed logs of chestnut or oak. He mentions indi- viduals having been found living far above ground in tall trees, in nests of birds of prey. One old male that was frequently seen by him always retreated far up a dead chestnut tree that towered above the surrounding forest of scrub pine. Mansueti also mentions arboreal combats between males and implies that they are territorial. Taylor (1936:59) described laticeps as typically an arboreal form, almost invariably found in trees, and he indicated that it has claws more curved than in other species — an obvious arboreal adaptation. Parker (1948:25), however, stated that "£. laticeps is reputed to Life History and Ecology of Five-lined Skink 15 be rather arboreal, but field work in western Tennessee has not borne out this belief. A few of the specimens have been found in tall, dead trees, as has E. fasciatus." This statement evidently was based on a small number of observations. Cook (1943:15) mentions a female laticeps found in a nest with a clutch of 27 eggs ( hence certainly a communal nest of two or more females) in a burrow under a log, on July 8, 1941, in Lee County, Mississippi. This account is under the name Eumeces fasciatus but tlie large size of the female precludes the possibility of it being either fasciatus or inexpectatus. The remainder of Cook's account is evidently based on a composite of observations on all three species. Coin and Coin (1951:29-33) have given an excellent brief ac- count of behavior and seasonal schedule in a small colony of E. laticeps near Gainesville, Florida, based on almost daily observa- tions over a period of years. In view of the greatly different cli- matic conditions, the seasonal schedule is remarkably similar to that of £. fasciatus in Kansas, and it seems that the minimum thres- hold temperatures required for activity are much higher in laticeps. Temperatures of 80° F. or above for several consecutive days seemed to be a necessary stimulus for emergence from hibernation; emergence was in the last week in March or the first week in April in Florida. Hatching was found to take place in late June or early July. Adults were last seen before retiring into dormancy in the latter half of September and young of the year remained active into October some two or three weeks later. The skinks observed all lived in hollow water-oaks. When the population was at an es- pecially high level, in the late summer of 1949, each hollow oak was inhabited by one young and one adult. Territoriality and mutual exclusiveness of adults and even of young seems to be implied. The skinks were seen eating spiders, ants, and cockroaches. Neill (1950:115) mentions one sizable colony of E. laticeps living in a treeless urban area, in Georgia and depending for shelter on piles of metal drums and other industrial equipment. Evidently, however, this was an exceptional situation. In another paper, Neill (1948b: 109) described the specialized hibernation site require- ments of laticeps in Georgia; the skink retires inside large, rotting pine stumps, especially those that are leaning. He states (1948a: 157) that in Georgia, laticeps is most common in the Coastal Plain and is much less numerous above the Fall Line (the line be- tween the Coastal Plain and the Piedmont). Deckert (1918:31) wrote of "Plestiodon fasciatus" in the vicinity of Jacksonville, 16 University of Kansas Publs., Mus. Nat. Hist. Florida, where only E. laticeps and E. inexpectatiis occur: "Inhabits hollow trees, always near water. Blue-tailed ones often live around human habitations." With regard to the ecological traits of E. inexpectatiis that dis- tinguish it from fasciatus, authors are much less definite, and evi- dence is somewhat conflicting as the differences are relatively minor. Engels (1949:269) noted the occurrence of E. inexpectatus on two low islands of submarine origin, off the North Carolina Coast, Harkers Island and Shackelford Banks, and he surmised that the absence from them of E. fasciatus and E. laticeps must have some ecological significance, since all three species occur on the adjacent mainland. Most of the island inexpectatus were taken from beneath loose bark of standing trees, while mainland fasciatus was taken from beneath loose bark of fallen trees. Barbour and Carr (1940:129) wrote of inexpectatus in the vicinity of Miami, Florida: ". . . it seems to be the only one [of the five-lined skinks] which has adapted itself to life under the rather specialized environmental conditions existing in its rocky and de- cidedly tropical habitat. It is one of the very few forms which have established themselves on some of the waterless and poorly vege- tated islands on both coasts of the peninsula. E. inexpectatus is much less arboreal than either laticeps or fasciatus. Altliough it climbs trees when pressed, it is usually found on the ground among leaves or about fallen logs, and particularly about stone walls or old buildings made of cut rock." On the other hand, Neill (1948a: 157) states that in Georgia, inexpectatus is often observed basking on tree trunks, and though adults often forage on the ground, they dash for the nearest tree when disturbed, usually climbing to a considerable height before halting. The juveniles, however, are said to climb only rarely; they hide beneath objects on the ground when they are pursued. Neill stated that E. inexpectatus occurs in dry pine forests where laticeps and fasciatus are lacking, as well as in moist or even swampy woods. E. inexpectatus often forages on the sides of old buildings. Hoffman (1953:172), in discussing means of differentiating be- tween inexpectatus and fasciatus in Virginia, states that there are ample differences in color and behavior as well as in scalation. He describes the color difference ( blue color of tail of juveniles extend- ing anteriorly beyond pelvis; light stripes reddish-orange on head, sublatcral line f)resent, in inexpectatus) but he does not describe the differences in behavior. He states that inexpectatus is the most abundant lizard in southeastern Virginia. Carr (1940:76) also Life History and Ecology of Five-lined Skink 17 states that inexpectatus is less arboreal than laticeps and is often found under logs and boards in dry sand. E. inexpectatus thus seems to be adapted to a somewhat drier, more open, habitat than that typical of fasciatus, but it is not clear whether either species is more arboreal in habits. It is to be hoped that the present inconclusive summary will draw attention to the problem and will lead to more critical comparisons of the habitats and behavior of the two species by herpetologists in the southeastern states. The differences, both ecological and morphological, that distinguish inexpectatus from fasciatus are of a degree usually found between subspecies of the same species. The extensive geographic 32 Fig. 4. Geographic distribution of Eumeces inexpectatus, as indicated by published records; only marginal and near-marginal records are shown, exclud- ing those of doubtful validity. overlap between them is indeed remarkable in view of the slight degree of differentiation, morphologically and ecologically. They are, however, complementary in part in their ranges, while laticeps shares all parts of its range with either one or the other, or both of them ( see Figures 4 and 5 ) . Under present conditions, with these three species so similar in habits and so extensively overlapping in geographic range, it is difficult to visualize a barrier such as would have been required for allopatric speciation of the type, usual in vertebrates, to have oc- curred. One might be tempted to postulate sympatric speciation, with the parent form, presumably fasciatus, giving rise to the other 2—3559 18 Unr'ersity of Kansas Publs., Mus. Nat. Hist. two by abrupt mutations. However, the demonstrable antiquity of the five-hned skinks would allow ample time for divergence, allopatric speciation, and subsequent disappearance of the barrier and intenningling of populations. The displacement of floras and faunas that occurred in the Pleistocene, with the successive advances and retreats of the continental ice sheets might have had some part in bringing about the present overlapping distribution, after the disappearance of the original barrier. Such a barrier might have been an eastward extension of the central grasslands to the Atlantic Coast at a time when the climate of the continent was warmer and drier. 32 32 Fig. 5. Geographic distribution of Eumeces laticeps, as indicated by published records; only marginal and near-marginal records are shown, exclud- ing those of doubtful vahdity. Habitat and Limiting Factors Temperature and Moisture Relations For approximately half the year, at the latitude of northeastern Kansas, five-lined skinks are dormant. In early fall, even before the advent of cold weather, they are hard to find apparently having begun their retirement into the sheltered situations where they spend the winter, even though they may not be fully dormant at that time. Remarkably little is known of the hibernation habits of this species or of reptiles in general for that matter. The hmit of toler- Life History and Ecology of Five-lined Skink 19 ance to low temperatures, the type of insulating medium, the mois- ture relationships, the specific stimuli which cause the animal to retire to its hibernation site or to emerge from it have not been de- termined. On only a few occasions have natural hibernating sites or the dormant skinks in them been observed by zoologists. Lins- dale (1927: 78) recorded one found in a sawdust pile late in the winter of 1924 in Doniphan County, Kansas. Hamilton (1948: 211) found skinks of this species hibernating in Grant Parish, Louisiana,^ in hollow logs 18-20 inches in diameter, five in one log and three in another, on January 23, 1943. Frost in the damp wood almost reached the lizards, which were in a torpid condition. These ob- servations were made when the temperature was 36°F. after the weather had begun to moderate following an unprecedented four- day cold wave when temperatures dropped to within a few degrees of 0°F. In both logs the skinks were accompanied by hibernating anoles (Anolis carolinensis) . Neill (1948b: 109) in Richmond County, Georgia, found E. fasciatus hibernating in old stumps, fallen timber, piles of debris, or beneath rocks and ground htter. Beneath scraps of rotting wood he often found dead, frost-rimmed specimens which apparently had frozen to death. Hibernating skinks of this species were found singly or in pairs. Some were not fully dormant when found but could only gape and twist when uncovered. Of hibernating E. laticeps, Neill wrote, "Many examples are covered with a waxy exudation, which I beheve to be a secretion of the lizard itself, rather than of the surrounding medium. This exudation has been noted in other species also." Scott and Sheldahl (1937:192) described a hibernating aggregation of Eumeces sep- tentrionalis found in Palo Alto County, Iowa, on February 15, 1937, as follows : "The skinks were found beneath a ledge of yellow clay about four and one-half feet below the surface. The lizards, 52 in number, were assembled in a compact group about the size and shape of a football. A soft, web-like material surrounded the mass and adhered to the bodies of the animals. Upon being uncovered some of them exhibited signs of life; others were dead." Brecken- ridge (1943:595) reported that a gravel digging crew found hiber- nating E. septentrionalis in late October and in January at depths of two feet (one), and three feet (groups of three and eight). Tihen (1937:405) recorded that two five-hned skinks found on January 13, 1948, were hibernating eight feet underground at Ban- son, Ness County, Kansas. This locality is far to the west of the main range of fasciatus. Conant (1951:30) mentions the finding 20 Untvtrsity of Kansas Publs., Mus. Nat. Kist. in Ohio of a young blue-tailed skink under a log where it seemed to be hibernating, on January 22. The spot where it was resting was soggy, and surrounding areas were covered with several inches of water. In the course of the present study, no five-Hned skinks were found hibernating under natural conditions, but on numerous occasions in early spring, two or three or four skinks were found together under massive flat rocks in semi-torpid condition, beside deep holes or crevices which presumably led to their hibernation sites in better insulated cavities. In the winter none could be found in such situations under large rocks, nor in the superficial t\'pes of hibernation sites described by Neill and Hamilton in the southern states. In the more severe winter climate of Kansas better pro- tected hibernation sites are required. In the rock ledge situations where skinks were studied, excavation for the purpose of finding hibernating individuals was not practical. On several occasions when skinks were put in the freezing com- partment of a refrigerator and frozen solid, at temperatures several degrees below freezing, they failed to revive when warmed. How- ever, they can survive temperatures a little below freezing. On April 1, 1953, one was placed in the freezing compartment with a thermometer inserted rectally. After 2/2 hours when the compart- ment was opened, this thermometer showed a temperature of — 2.5°C, after a delay of several seconds in obtaining a reading be- cause of condensed moisture on the thermometer obscuring the mercury column. Another thermometer that rested beside the skink in the compartment showed 27°F. The skink was limp and immobile. It was placed on a table top at normal room tempera- ture, and it warmed rapidly. When it had reached 1.5°C, it con- tracted its muscles in response to a light pinch. At 9.5^C it raised its head and had its eyes partly open. Twenty minutes after its removal from the freezing compartment, it was still lying in the same position, its temperature having reached 13.5°C. When handled it seemed dazed for several seconds as if just awaking. Then it crawled away briskly. On March 28, 1953, a skink was placed in the freezing compart- ment for about 10 minutes, and upon removal its temperature was recorded as — .5°C. It was not frozen, but was limp and unrespon- sive to such stimuli as pinching or pricking. At 1.5°C feeble move- ments of the legs were noticed. The eyes were still closed. At 3.4°C the legs moved as if in walking. At 6.0°C the skink raised its head and took several steps forward. At 7.5°C it protruded its Life History and Ecology of Five-lined Skink 21 tongue and dragged itself about for several steps. At 9.0°C move- ments of the sides indicated an inspiration approximately every three seconds. At 12.2°C it opened its eyes. On March 25, 1953, a skink that I had caught the day before and left overnight in an unheated room, was found to have burrowed into loose earth in its container. When exposed, its temperature was 1.8°C and it was unable to crawl normally, but took only one step at a time, and progressed with slow lateral squirming motions. Placed on the ground outside the building, in the shade where there was still a little frost, it moved forward persistently for several inches trying to burrow into the surface litter. After a few minutes, its eyes were shut and it seemed incapable of further locomotion. Its temperature was 1.4°C. When placed on its back it was able to turn over slowly after several seconds. A few minutes later its temperature was 0°C, and it was totally helpless, although still capable of feeble movement. When stimulated by touch, it flexed its body a little, or moved each limb slowly in an arc as if walking, the movement taking several seconds. Placed on its back or side it was unable to right itself. Less than three hours later I saw a skink tliat was active in the field. Slight movement at the edge of a rock that was exposed to sunshine attracted my attention and turning the rock I found the skink underneath, lively enough to scramble for shelter but slow and stiflF compared to those that are fully active. Its temperature was 13.5°C and air temperature was 7.5°C. In damp soil beneath the rock where the lizard was found, temperature was only 5.7° C. It seemed that the skink had been suflBciently warmed by contact with the undersurface of the rock to move into the open, and was just emerging when I approached. After capturing the skink, I set it on a rock in the sunshine, and in five minutes its temperature had risen to 26°C. As compared with its reptilian associates in northeastern Kansas, Eumeces fasciatus is outstanding in its ability to become active and carry on normal activities at relatively low air temperatures. In spring it is usually seen in the open before any other kind of reptile, because it has the capacity to move about sluggishly at temperatures so low that some other reptiles are numbed and com- pletely immobilized, and because it has small size enabHng it to make rapid adjustment upward by insolation, or contact with sun- shine-warmed surfaces. By virtue of this abihty it has been able to extend its range farther northward than most other reptiles, and it has gained the advantage of a longer growing season. This advan- 22 University of Kansas Publs., Mus. Nat. Hist. tage was especially apparent in the spring of 1953. A mid-March warm spell with seven out of eight successive clays having maximum temperatures in the sixties culminated on March 20, with a maximum air temperature of 82°F. This warmtli was sufficient to activate most of the five-lined skinks, and a few reptiles of other kinds. After the unseasonably high temperature of March 20, there was rapid return to cooler weather with temperatures frequently below normal throughout April. As a result there was little activity of other kinds of reptiles that month, but five-lined skinks were active on most days. On only a few days, those with temperatures in the low forties or those on which the sky remained overcast, did the skinks remain inactive. On most days maximum temperatures were in the fifties and sky was clear. Under these conditions the skinks were able to emerge and bask, rapidly raising their body temperatures far above those of the air and substrate. By the end of April some kinds of deciduous trees have not yet begun to leaf out, and in most other kinds the leaves are still in an early stage of development. Absence of a leaf canopy during April permits the skinks to utilize the spring sunshine to maintain their body temperatures at almost the same high level that they maintain in the same situations in hot summer weather. Table 2. Temperatures ( in Degrees Centigrade ) of Skinks Found Under Flat Rocks Exposed to Sunshine, Contrasted With Air Temperatures; Spring of 1953. Date Age and sex Skink temperature Air temperature March 23 . March 23. March 25. March 25. March 25. March 25. March 27. March 27. March 27. March 27. March 27. March 27. Apr Apr Apr Apr Aj)ri Apr Apr: Apr Apr: 14. 15. 16. 6. 6.. 6.. 6.. 6.. 20. April 20. Ad. 9 young Ad. cf young young young Ad. c?" young Ad. 9 Ad. 9 Ad. 9 Ad. 9 young Ad. 9 Ad. cf Ad. cf Ad. Ad. Ad. Ad. Ad. Ad. 9 9 9 9 9 20.8 24.7 22.8 21.0 25.7 22.5 26.6 22.0 22.5 20.5 26.5 30.7 22.0 26.0 31.5 23.7 22.2 20.0 20.0 26.5 29.7 25.8 12.4 12.4 12.5 12.5 14.5 14.5 16.5 16.5 16.5 16.2 19.3 19.3 18.1 13.0 13.5 16.0 16.0 16.0 16.0 20 17 17. Life History and Ecology of Five-lined Skink 23 Recent studies by Cowles and Bogert (1944:288-289) and Bogert (1949:198) have brought out the fact that terrestrial poikilotherms, and especially lizards, maintain fairly high and constant body tem- peratures through behavioral thermoregulation, during their periods of activity. For genera and species of lizards, there are optimum body temperatures, which the individual tends to maintain, fluctuat- ing v^ithin a range of only a few degrees while it is active. Forms that are not closely related may diflFer notably in their optimum temperatures, although within any one genus the range is slight. For example in the iguanid genus, Sceloporus, Bogert found that different species from such distant regions as Arizona and Florida agreed in having body temperatures approximating 35° or 36° C, while different members of the teiid genus Cnemidophorus in the same two regions were found to approximate 41° C. in mean tem- peratures. In commenting on the distribution of North American lizards as affected by opportunity for behavioral thermoregulation by direct insolation, Bogert (op. cit. :205) wrote: "Such secretive hzards as skinks (principally Eumeces in North America) with low body temperature preferences approximating 30° C. are dominant in Florida and the Gulf Coast, in contrast to the Teiidae and Iguanidae ( several genera in the United States ) , which are far more abundant in the arid regions of the Southwest." Bogert and Cowles (1947: 19 ) record that in a large individual of Eumeces inexpectatus taken near the Archbold Biological Station in Florida, the body tempera- ture was 33.2° C. In the 1952 season, a small thermometer of the type described by Bogert ( op. cit. : 197 ) was frequently carried on collecting trips, and cloacal temperatures were recorded for the lizards collected. For those found in traps the opportunity for behavioral thermoregula- tion was limited, and temperatures usually approximated those of the air. The circumstances of capture, and the air temperatures were recorded for most of the skinks taken. For those found under rocks or in other shelter, the temperature usually approximated that of the immediate surroundings, and averaged much lower than for those taken in the open, but some found in such shelters had tem- peratures many degrees higher than their surroundings, and were fully active, having evidently just taken to cover to escape notice as the collector approached. As soon as a lizard was secured it was held in a leather glove or heavy cloth to prevent conduction of heat from the collector's hand, and a reading was taken within a few seconds. Most of the skinks found in the open could not be caught immediately but were secured only after minutes of maneuvering on the part of both collector and lizard. In most instances this 24 Uxn'ERSiTi' OF Kansas Publs., Mus. Nat. Hist. maneuvering probably entailed some loss of heat by the lizard, as it interrupted its thermoregulatory behavior to run to a place of con- cealment, usually in shadow on a tree trunk, or in or beneath ground litter. Excluding all those not found active in the open, the mean temperature, in a sample of 41, was 31.5° C. ± .60. This figure is thought to be slightly too low because of heat loss by many of the skinks in the time required to capture them. In order to test the range of tolerance and verify the preferred optimum temperature of the five-lined skink, an experimental ter- rarium was set up providing extremes of temperature at each end. A false floor of M inch wire screen was provided, with a seven-inch strip of galvanized sheet metal beneath it at each end. Beneath the screen and sheet metal at one end the space was filled with chopped ice, and "dry ice." Observations were made on hot, clear summer days, with the terrarium arranged so that the half of it containing ice, was in shadow, and the other half was in sunshine. The strip of metal, warmed by direct sunlight, became uncomfortably hot to the touch while at the other end the sheet metal and overlying screen were cooled by the ice. A narrow zone across the middle of the terrarium had screen but no underlying sheet metal and was the only part within which the lizard could maintain normal tem- perature, one end being uncomfortably hot and the other end too cool. A large dead skink left on the metal strip in direct sunlight for five minutes had a cloacal temperature of 45.3° C, and after five minutes on the screen at the cool end, its temperature had dropped to 25.5° C. On several occasions a number of skinks were put in the terrarium and their temperatures taken at brief intervals. Tem- peratures ranged from 21.6° C. to 37.7° C. but were mostly within a much narrower range, from 28° to 36° C. One skink that seemed to be sick was sluggish in behavior, not responding to the extremes of temperatures as readily as the other individuals and his tempera- ture fluctuated widely and irregularly. Ehminating this individual, 66 temperature readings taken, from five other skinks, gave a mean of 32.6° C. ± .235. While nearly all the temperature readings were within a range of ten degrees, two of the readings were outstand- ingly low and perhaps should be discarded. If this is done, a mean of 33.8° C, ± .19 is obtained for the remaining 64. There is distinct bimodality in this series however, with a mean of 34.2° for the 49 higher readings, and a mean of 28.8° C. for the 15 lower tempera- tures. A similar bimodality is evident in the readings obtained from skinks caught in the open imder natural conditions. It seems that the lower readings result from lags in the skinks' response when Life History and Ecology of Five-lined Skink 25 body temperature drops slightly below the optimum. The skink is quick to make adjustment whenever its temperature appreciably exceeds this optimum level, and is in extreme discomfort at only a few degrees higher temperature. At slightly lower temperatures, however, the skink experiences no discomfort, and only slightly de- creased eflBciency in its various functions, and its thermoregulatory behavior in making readjustment toward the optimum is likely to be leisurely and interrupted unless its temperature drops below 28° C. Catching the skinks in the experimental terrarium at frequent intervals to take their temperatures involved some disturbance to them, interrupting their thermoregulatory behavior. The experi- menter's first attempt to grasp a skink sometimes failed, and it then dashed about the terrarium for several seconds, probably altering its temperature somewhat. Nevertheless most of the lizards' move- ments were motivated by thermoregulation. This was especially evident when they were left undisturbed, and is illustrated by the following notes on behavior of an adult female and half-grown young of fasciatus and a young E. ohsoletus on the afternoon of July 21, 1952. 2:58 All resting over cooled metal. 3:01 Female runs to line of sunshine and shadow, coming to rest with ap- proximately half her body in sunshine, the other half in shadow over the cooled metal. 3:03 Female reverses position so that hindquarters previously in shadow are now in sunshine, and forequarters are in shadow. 3:03/2 Young runs to middle coming to rest in sunshine on screen. 3:04 Female moves back to the cool end. 3:05 Young moves to edge of cooled metal but not over it, in a narrow middle strip that has sunshine. 3:05/2 E. ohsoletus moves from cool end to middle, partly in sunshine. 3:07 E. ohsoletus adjusts its position in narrow middle strip of shadow just off the cold end. 3:08 Boards used for shading adjusted back slightly so that E. ohsoletus is in sunshine. 3:08/2 E, ohsoletus moves back to cold end. 3:10 Young still at middle, but resting mainly over cooled metal with tail partly in sunshine. 3:10/2 Young moves out into sunshine at middle. 3:11 Female moves out into sunshine at middle. E. ohsoletus moves over cooled metal to its edge, coming to rest partly in sunshine. 3:12 Female moves back over cooled metal. 3:1332 Air temperature 33.3°C. E. ohsoletus shifts a short distance so that it is resting entirely over the cooled metal, with only part of its tail receiving sunshine. 26 Unr'ersity of Kansas Publs., Mus. Nat. Hist. 3:17 Young moves about in sunshine, tlien comes to rest in shadow with half its body over cooled metal. 3:19 Young shifts so that more than half its body is in sunhght in middle section. 3:20 Young shifts away from sunlight, coming to rest with most of its body over the cooled metal. 3:21J2 Female moves from cooled metal to sunshine in middle strip. 3:23 Female moves out of sunshine, partly over edge of cooled metal. 3:30 Young moves off cooled metal, coming to rest over edge of warmed metal in narrow middle strip that is in shadow. 3:30/2 Young moves back away from warmed metal, pauses briefly, and then moves over cooled metal coming to rest there. 3:31 Female shifts so that about half her body is in sunsliine in the middle. 3:32 Female shifts back into shadow, partly over cooled metal. 3:33 Boards providing shade readjusted so that female is in sunshine. 3:33/2 Female moves back into shadow over cooled metal. 3:38 Female moves to edge of cooled metal, resting partly in sunshine; sky is becoming slightly overcast. 3:40 Temperature of female 33.4°C. 3:41 Temperatiire of young 32.8°C. 3:43 Temperature of E. obsoletus 32.4°C. 3:45 Young moves to shaded edge of warmed metal. Finds a dead spider dropped there and eats it. 3:47 Temperature of female 32.3°C. 3:48 Temperature of young 36.4°C. 3:50 Temperatiure of E. obsoletus 33.8°C. 3:52 Sky partly overcast with thin layer of clouds; observations concluded. Having once emerged from its hiding place a skink becomes more or less independent of the temperature of the air and sub- strate, as it is capable of thermoregulation tlirough insolation. However, after a period of cooling and inactivity in dormancy, or merely resting for the night in temporary shelter, the skink is de- pendent on warmth from the air or substrate or botli to become sufficiently activated so that it can emerge and take advantage of direct sunlight. About 10:00 a. m. on April 13, 1951, when the air temperature was a little less than 10°C., a large adult male rusthng among dry leaves attracted my attention. Obviously recently emerged from hibernation, he was caked with dried mud and his eyelids were nearly sealed shut. He had been sunning, however, and was active enough to elude my attempts to catch him, as he scurried into a deep crevice under the ledge. On the morning of March 24, 1951, while the temperature was still between 10° and 15°C., a subadult skink, the first one of the season, was seen sun- Life History and Ecology of Five-lined Skink 27 ning itself at the entrance of a deep crevice under the ledge. This skink was still not fully active, and its movements were stiff, yet it was alert and wary, and it quickly retreated back into the crevice. During the first week of May, 1952, skinks were active in abundance and numbers were caught daily in funnel traps and pitfalls. On May 9, however, the maximum air temperature was 16.5°C. with cloudy sky and occasional showers. Under these con- ditions skinks stayed under cover; none was seen in the open nor caught in a trap, and several found under rocks were slow and sluggish. On May 10 a terrarium with several adults was placed in dilute sunshine beside a window in an unheated room. After a period of basking the skinks were stimulated to activity, but were unable to attain normally high temperatures, and as a result their movements were like slow motion caricatures of the normal be- havior. Males approached each other with menacing demeanor, with heads turned, snouts depressed, and forequarters standing high. Frequently one would edge up to another and bite hard at its flanks. The several males were sexually aroused by the presence of the two females, but were capable of only the preliminary phases of courtship, in delayed and protracted form. The temperature of one was 18.2°C. when the sun had nearly set and activity was tapering off, at an air temperature of 16.2°C. At 16°C. skinks in a terrarium with no access to sunshine for the most part showed no interest in food and kept out of sight under cover. When exposed their activity was directed almost entirely toward burrowing into the substrate or searching for objects beneath which to hide. One adult female was partly exposed by scraping away loose soil into which she had burrowed. A mealworm was then dropped just in front of her head. She tested it several times with her tongue and then ate it without emerging, her movements being much less brisk than they normally are in feeding. Probably this approximates the threshhold temperature for feeding behavior. At 19.5°C. the sev- eral skinks in this terrarium were moving about in the open al- though they were not exposed to sunshine, and they accepted food avidly when it was offered, but were much slower than at optimum temperatures. On May 16, 1951, when a pair of skinks were put together in a terrarium in the laboratory at 21°C., copulation en- sued but it was of longer duration than in other observed instances, seemingly because of the relatively low temperature. Relatively few temperature readings on gravid or brooding fe- males under natural conditions were obtained as they were easily disturbed and tended to desert their nests at shght provocation. 28 UxrvERSiTY OF Kansas Publs., Mus. Nat. Hist. To avoid desertions handling was kept to a minimum. Occasionally gravid females were caught in the open, but most of them were in nest burrows under flat rocks. These females found in nests were mostly cold to the touch, and the temperature readings taken on some of them usually approximated the air temperature, being either higher or lower (depending on whether the air was cooling or warming and whether the lizards were warmed by contact with rock or soil receiving sunshine ) . On May 23, 1952, 22 skinks were seen, four adult males, seven adult gravid females, and 11 young. Of these the adult females all were in nest burrows, and were cold and slow; consequently all of them were caught without difficulty. The males and young, however, were either fully warmed or warm enough to escape rapidly, so that only three of the young and no adult males were caught. Temperatures of the females tested were 25.6°, 23.6°, 23.5°, 22.3°, and 19.4°, and for the three young, 32.8°, 28.4°, and 28.4°. Air temperature varied from 20.5° to 24.8°. For the total of 30 females in nest burrows whose temperatures were taken in 1952, the average was 26.3°C., ranging from 16° to 34°. Gravid females, and those with nests and eggs were rarely seen in the open. The five-lined skink is confined to a region where summer rains are frequent. It is evident that a regular supply of drinking water is one of the most critical ecological requirements. Bogert and Cowles (1947:19) found that an E. inexpectatus experimentally kept at high temperature lost moisture at a more rapid rate than any other reptile tested (including two other kinds of lizards, four kinds of turtles, an alligator, and three kinds of snakes). They remarked that this rapid moisture loss presumably accounts for the inability of skinks to survive in containers when no moisture is readily avail- able, and also accounts for their absence in truly arid habitats. The Natural History Reservation is situated near the western edge of the species' range in a climate that may be near the limit of its range of tolerance. However, on most summer mornings low wood- land vegetation is copiously laden with dew, and this evidently fulfills the need for drinking water. Diminution of surface activity and retirement to underground retreats seem to be closely cor- related with cessation of rains in late summer. After rainless periods in August and September, when morning dew is no longer available these skinks, especially the adults, are no longer regularly seen in the open. They have retreated to underground shelters where they spend nearly all their time. The time of disappearance varies from year to year and the correlation with varying weather Life History and Ecology of Five-lined Skink 29 conditions seems obvious. While no actual experiments were per- formed to determine the moisture requirements, it is evident that the need for moisture rises sharply with increased temperature. Skinks that are dormant in hibernation survive for periods of months without drinking, with but little loss of weight. In their under- ground shelters temperature is low and presumably relative humidity is high. At temperatures above their optimum of approximately 34° C. the skinks are especially subject to rapid moisture loss, since evaporation of body moisture is resorted to as a device to keep the temperature below the lethal level. The skinks subjected to extremes of temperature in an experimental terrarium were seen to lap up condensed moisture on the cooled metal plate at intervals of a few minutes. After an hour or more in the experimental ter- rarium they seemed somewhat debilitated. Skinks brought from the study areas to the laboratory for weighing and other records, were ordinarily returned on the following day. When circumstances prevented adherence to this schedule in hot summer weather, mor- tality could be expected in the skinks kept in cloth bags or glass containers, unless water was provided. Dramatic weight loss of up to more than 30 per cent was recorded in some individuals, kept at the high temperatures which usually prevailed in the laboratory, over periods of days in the summer. Skinks having access to drinking water often ingest amounts far beyond their immediate requirements, which may be stored in the bladder and drawn upon over periods of days as it is needed, or may be utilized to dampen the soil of the underground shelter and raise the humidity, as incubating females seem to do. Geographic Range and the Deciduous Forest Habitat Eumeces fasciatus corresponds in its distribution with the original hardwood forests of eastern North America, as mapped by Braun (1950: cover folder) and the "Oak- Wild Turkey Biome" of Shelf ord (1945:240). Few species of vertebrate animals have ranges that coincide more closely with this extensive area (exclusive of the northern edge, that part characterized by Braun as the Hemlock- White Pine-Northern Hardwoods). This latter is a mixed forest which actually is transitional between the more typical deciduous forest farther south and the Taiga Biome (or Formation) to the north, which is dominated entirely by conifers. At the northern edge of its range Eumeces fasciatus is much less generally dis- tributed than it is farther south. Although it is well established and even may be locally numerous in South Dakota, Minnesota, Wiscon- 30 Unt^-ersity of K.\nsas Publs., Mus. Nat. Hist. sin, northern Michigan, Ontario, northern New York, and Con- necticut, the locality records from these states are few, and seem- ingly represent isolated and widely separated colonies that are able to persist because of favorable combinations of environmental factors not of general occurrence in the surrounding regions. Figure 6 shows the extent of the hardwood forests as mapped by Braun (excluding the transitional Hemlock-White Pine-Northern Hard- woods Association) with specific locality records of E. fasciatus included in all outlying portions of the range. The locality records are those published by Taylor (1936:206-212) supplemented by other marginal records, more recently published, by Hamilton (1947:64) for New York, Breckenridge (1944:97) for Minnesota, Hudson (1942:42) for Nebraska, Smith (1950:185) for Kansas, Brown (1950:116) for Texas, Neill (1948:156) for Georgia, and Neill and Allen (1950:156) for Florida. Along the nortliern edge of its range, the skink invades the Hemlock-White Pine-Northeni Hardwoods Association, in Massachusetts, New York, Pennsylvania, Ontario, Michigan, and Wisconsin, but does not penetrate far into it anywhere. Correspondence of its northern limits with those of the Oak-Chestnut, Maple-Basswood, Beech-Maple and Oak- Hickory associations is remarkably close, considering the fact tliat the boundaries of these climax associations are not sharply defined; rather they merge by gradual stages into the northern coniferous forests, with outlying peninsulas and islands where conditions are favorable. The outlying northern localities where E. fasciatus occurs within the Hemlock-White Pine-Northern Hardwoods Association are all within the region of Pleistocene glaciation, which 20,000 years ago, or even more recently, were covered with the continental ice mass during Wisconsinan time. Yet the localized northern populations of skinks evidently are relicts from a time when favorable condi- tions were more widespread in the general region. Braun (op. cit.: 464-465 ) indicates five successive postglacial stages in the trends of climate up to the present, as revealed by bog pollen profiles: (1) Cool and moist; (2) warm and dry; (3) warm and humid; (4) warm and dry; (5) cool and moist. Stages 2 and 4 would have been most favorable for encroachment of the skink into glaciated regions, whereas stages 3 and 5 might have caused retrenchment of its populations. In view of the localized habits of individuals, and the lack of any mechanism for rapid dispersal, the time available seems no more than adequate for the distance of 200 miles or more north- Life History and Ecology of Five-lined Skink 31 ward that the skinks must have moved since the final retreat of the ice sheet. This northward movement involved crossing of formi- dable barriers such as the Great Lakes. Even minor barriers such as small rivers and creeks, might be expected to halt population movements for long periods. Fig. 6. Geographic distribution of Eumeces fasciatus as indicated by pub- lished records (marginal and near-marginal records shown, excluding those of doubtful vahdity ) . ( 1 ) Distribution of the Deciduous Forest Formation of eastern North America, as mapped by Braun (1950), but excluding the Hem- lock-White Pine-Northem Hardwoods Association that is transitional to the more northern coniferous forests. (2) The shaded area in Kansas that is outside the Deciduous Forest Formation comprises the Kaw River District, Cherokee Prairie District, and southern Osage Savannah Biotic District (Cockrum, 1952). The over-all geographic range is approximately square, roughly a thousand miles across, from north to south and from east to west. On the east and south it is Hmited by the Atlantic Ocean and the Gulf of Mexico. On the north and west its Hmits correspond with those of the hardwood forests. On the northwest, it reaches south- western Minnesota and the southeastern corner of South Dakota, 32 Unr-ersity of Kansas Publs., Mus. Nat. Hist. extending fiir out into peninsular extensions of the Oak-Hickory Association which penetrate westward into the prairies along the main river valleys. In Kansas it occurs over the eastern one-fourth, west to the Flint Hills, and a little farther west in peninsular extensions of the forest along some of the main river valleys. In Braun's map the Deciduous Forest Biome is shown to reach only the eastern edge of Kansas along the Kaw River and Missouri River at and near their junction, the Osage (or Marais des Cygnes) River valley near the Missouri border, and the southeastern corner of Kansas. However, for almost 100 miles farther west from the Missouri border, the country has the aspect of a savannah with scattered groves of trees on hillsides and along streams, providing suitable habitat. The distribution of the five-lined skink in eastern Kansas corresponds well with certain "Biotic Districts" as mapped by Cockrum (1952:12), namely the Kaw River, Osage Savannah (southern part), and Cherokee Prairie. Conversely the skink is excluded from the Short Grass Plains and Mixed Grass Plains Biotic Districts which occupy nearly all of the western three-fourths of the state. There are two specimens in the University of Kansas Natural History Museum, labelled Ranson, Ness County. This locality, in the western third of the state, more than 150 miles from any other recorded station, may represent an isolated colony; however Smith (1950:185) states that the record needs verification, and it is not included in the map. Figure 6. In Oklahoma the distribution records fit fairly well the portion of the state mapped by Braun as the Oak-Hickory Association of the Deciduous Forest, but extends a little farther west in the north- eastern part of the state. A game type map published by the Okla- homa Game and Fish Department, Division of Wildlife Restoration, in 1943 shows in more detail distribution of the main vegetation types within the state. The locality records for the skink fall almost entirely within three of the fifteen vegetation types mapped, namely, the oak-pine, and oak-hickory forest of the state's eastern edge and the post oak-blackjack oak type of the eastern and central parts. The locality records extend almost throughout the area occupied by these three types but not in attenuate westward extensions of the post oak-blackjack type that occur along several of the main stream courses. In Texas likewise the recorded localities fall mainly within the area mapped as deciduous forest, but with several slightly beyond its boundaries. In a detailed map of the "game regions" of Texas (Anonymous, 1945:1), some of these outlying localities fall into the coastal prairie area, and the remainder into the post oak Life History and Ecology of Five-lined Skink 33 and blackland prairie belts, which grade into each other and the oak-hickory forest. The former distribution of the five-Hned skink may be postulated on the basis of the fossil record of its community associates since it is a primitive and conservative type. Taylor (1936:56) explained the present discontinuous distribution of the genus on opposite sides of the world on the basis of a former northern connection of the continents. He wrote: "I regard migration from North America to Asia as having taken place via land bridges joining the Alaskan peninsula with Asia either at Bering Straits or via the Aleutian Island arc to Kamchatka, or both. One would need postulate but slight climatic changes since the present climate of this coastal region is probably no more rigorous than that of southern Canada which has three species of the genus." However, such former northward dis- tribution, while entirely probable, would have been possible only in a climate much milder than that which prevails at present. In Asia, tunganus on the mainland and latiscutatus on the island of Hokkaido extend north to about latitude 43°, and in North America, fasciatus extends slightly farther north. In order to have crossed between Alaska and Asia on presumed land bridges these skinks would have had to extend their ranges about 20 degrees north of their present limits, into what is now a cool climate. The winter climate of the Bering Sea is perhaps not much beyond the range of tolerance of the more cold-adapted forms of Eumeces, but the cold, cloudy, wet, and changeable summer climate is far beyond the range of tolerance of Eumeces or any other lizard. It is highly improbable that the fossil record will yield direct evi- dence for the existence of a northern ancestral Eumeces of the fasciatus group. The characters by which the various forms are recognized are to be found mainly in details of pattern and scala- tion; the skeleton is so conservative that specific characters are ill defined or lacking even in well preserved fossil material. This hy- pothetical ancestor probably was a member of a deciduous forest community having components in common with the modern forests where the American and Asiatic species occur, along with types now extinct, and others which, though existing at the present time, have become separated from their original associates and occur in other regions. Hollick (1936:11) has described a rich early Tertiary Alaskan flora strikingly different from that of the same region at the present time. Composed of genera now characteristic of warm-temperate to subtropical climates, it was remarkable in having many types of 3—3559 34 University of Kansas Publs., Mus. Nat. Hist. plants that are now most characteristic of the North American hard- wood forests in the southeastern part of the continent. Besides such widespread genera as Fagus, Betula, UJmtis, Flat anus, Cas- tanea, Corylus, Carpinus, Crataegus, Spiraea, Myrica, Smilax, Pinus, Picea, and Abies, this flora included others now characteristic of both warm-temperate southeastern North America and Eastern Asia, as Magnolia, Nyssa, Sassafras, Persea, Benzoin, HamamcJis, Liquidamhar, Celastrus, Nelumbo, and Onoclea. It included genera Carya, Taxodium and Comptonia that now are Umited to SE North America, Sequoia, now limited to western North America, and also included several genera which at present are limited to south- eastern Asia: Ginkgo, Ghjptostrobus, Cinnamomum, Housmannia, Artocarpus, DiUenia and Koelreuteria. This fossil flora provides strong evidence that in the early Tertiary climatic and habitat con- ditions as far north as Alaska were favorable for the existence of an ancestral Eumeces similar to the modern E. fasciatus, which might have given rise to both North American and Asiatic members of the fasciatus group. There is abundant evidence for the existence of an Eocene land connection between Alaska and northeastern Siberia, permitting free interchange of faunas between the two continents, as shown by the almost simultaneous appearance of various mammalian groups in the fossil records of Asia and North America. Simpson (1947:627) has summarized the evidence that such intermigrations were oc- curring throughout most of the Tertiary, with occasional interrup- tions as in middle Eocene, and in middle and late Oligocene, and with increasing selectivity, chiefly a progressive tendency toward screening out of the groups less tolerant of cold (judged on the basis of their modern representatives). In the late Tertiary, and especially in the Pleistocene, animals known to have made migra- tions between North America and Asia were types now character- istic of boreal climates ( e. g. pika, hare, vole, lemmings, marmot, jumping mouse, fox, wolverine, bear, moose, caribou, sheep, bison, camels, mammoth). Simpson believes that there was fairly strong climatic selectivity even in the Miocene interchanges, and he indi- cates several important groups that were non-migrants in the Mio- cene, most of them remaining so through the Pliocene and Pleisto- cene — the primates, Rhizomyidae, Gliridae, Viverridae, Hyaenidae, Dicerorhininae, Suidae, late Anthracotheriidae, Hippopotamidae, Tragulidae, Muntiacinae, Lagomerycidae, Giraffidae, and Bovidae. He states that there is good evidence that these are all mainly warm-climate animals which are not likely to have ranged in any Life History and Ecology of Five-lined Skink 35 force into a cold-temperate or boreal environment. In view of these conclusions it seems doubtful whether Eumeces or other reptiles could have crossed the Alaskan-Siberian land connection so late as the Miocene. On the contrary, the climate and habitat conditions with which Eumeces might have been associated, although present as far north as Alaska in the Eocene, evidently had shifted far to the south by mid-Tertiary time. Axelrod (1950:230) has described a Miocene forest of the Columbia Plateau and northern Great Basin indicative of a uniform temperate climate and an average rainfall of thirty-five to sixty inches. This forest included: (a) various genera now characteristic of the southeastern hardwood forest or confined to it — Canja, Castanea, Comptonia, Fagus, Liquidambar, Nyssa, Tax- odium; (b) other genera at present more characteristic of the west- ern United States — Sequoia, Lithocarpus, Pseudotsuga, Mahonia, Thuja, Gaultheria, Amelanchier; (c) wide-ranging genera including Alnus, Acer, Betula, Populus, Quercus, Picea, Pinus, Tsuga, Cornus, Ribes, Rosa, Hydrangea; (d) modern east Asian genera, including Ginkgo, Ailanthus, Glyptostrobus, Keteleria, Koelreuteria, Metase- quoia, Pseudolarix, Pterocarya, Zelkova, which were eliminated from the North American flora in the latter part of the Tertiary. In short, this western Miocene forest was remarkably similar in many respects both to the presumably ancestral early Tertiary Alaskan forest and the modern southeastern hardwood forest. The extent of this Miocene forest is unknown but judging from the sites where it has been recorded, it had progressed about halfway, both in latitude and in actual distance, from Alaska to the area occupied by the modern southeastern deciduous forests. Several other reptilian genera have distributions similar to that of the fasciatus group, with representatives in southeastern Asia and southeastern North Amer- ica that probably have parallel histories of distributional divergence from early Tertiary northern ancestors similar to contemporary species (Schmidt, 1946:148-150). Alligator, Natrix, Ancistrodon, Scincella, Elaphe, Opheodrys, and within the genus Eumeces, the obsoletus group, all provide excellent examples. Effect of Climatic Factors Accounts of the habits and habitat, by various authors, indicate versatility in behavior, and adaptation to a variety of habitat con- ditions in diflFerent climates and plant associations. Some of the differences evidently result from the skink's tendency to maintain itself in surroundings of favorable temperature and humidity, which 36 University of Kansas Publs,, Mus. Nat. Hist. obviously are to be found in different types of situations at different extremes of the range. Hence even though the skink itself may re- main unchanged, it tends to behave somewhat differently under di\"erse environmental conditions. Such environmentally enforced differences in habits would be difficult to distinguish from those having a genetic basis. Although no subspecies of Eumeces fasciatus have been recognized, local populations undoubtedly differ some- what in size and other characters that have a genetic basis. At the northern edge of its geographic range, fasciatus occurs in isolated colonies and seems to be restricted to open, rocky situations which receive the maximum amount of sunlight. Breckenridge (1944:96) wrote that at the two Minnesota localities representing the northwestern corner of the known range, the skinks were found at granite outcrops, and he mentions one found in western Wiscon- sin, at Taylor Falls, under an 18-inch slab of a basalt outcrop in sparse oak woods. Patch (1934:51) described a habitat at Arden, Ontario, among massive granite-gneiss domes, with sparse vegeta- tion. At Point Pelee, Ontario, the species is common in the drier, more sparsely wooded situations, hiding beneath loose bark of stumps and logs. Ruthven (1911:264) found £. fasciatus in the vicinity of sandy beaches in the Saginaw Bay region of Michigan. Elsewhere in its range it is more characteristically an inhabitant of hardwood forests, preferring the better drained and more rocky situations, according to the testimony of numerous authors. In eastern Illinois, Smith (1947:33) found it confined to the area south of the Shelbyville moraine, and not ranging into a prairie habitat. Near Elkville, Illinois, Cagle found the species abundant in higher and drier areas within sparse stands of oak in second growth woods, but it was absent from the low swampy areas adjacent to streams. Conant (1951:30, 210), describing the habitat in Ohio, stated that the spe- cies does not occur in swamps and areas that are subject to spring floods nor on dry hillsides, but is abundant in some areas where there are rotting stumps and logs remaining from former patches of swamp forest, and usually is found in low, moist situations, in wooded valleys or even at the edges of swamps and bogs. Lynn (1936:49) wrote that in Virginia, it is most often seen on steep, boulder-strewn hillsides and old sawdust piles. In tlie central Ozarks of Missouri, Owen (1949:49) found it abundant and saw it almost daily on rocky ledges, fallen timber, and fence rails, while E. laticeps was seen only once. Taylor (1936:59) wrote that E. fasciatus occurs where there is timber and is often found about fallen Life History and Ecology of Five-lined Skink 37 trees and rotting stumps, or about old sawmills where wood refuse has accumulated. Smith (1950:187) wrote that in Kansas the spe- cies is commonly found in wooded areas in moist situations about stones, leaves and rotten logs. Gloyd (1928:120) wrote that in Franklin County, Kansas, E. fasciatus occurred in upland situations and was the most abundant lizard where there were rocks, brush, or decaying wood. Gloyd (1932:401) also recorded it as abundant in the Pigeon Lake area, Miami County, Kansas, in wooded areas of sufficient elevation to be out of the river flood-plain. Habitat in Northeastern Kansas In northeastern Kansas I have collected or observed this skink in several dozen localities, and searched unsuccessfully in numerous other localities. Absence of this skink, in some situations and its presence and relative abundance in others, provided a basis for appraising the environmental factors that are of critical importance. River valleys, of the Kaw and Wakarusa and their tributaries, with deep alluvial soil, alternate with flat or rolling upland some two hundred feet higher in elevation, and having shallow, rocky soil. Where the uplands slope to the valley floors, there are steep hill- sides, usually with extensive limestone outcrops along their upper slopes. The alluvial plains formerly supported hardwood forests, while the hill slopes and uplands were largely prairie. At the present time the bottomland forest has been almost completely de- stroyed, as it grew on the most fertile and potentially productive soil, and has been replaced by cultivated crops. There are still trees along streambanks, and in occasional woodlots, but I have failed to find any skinks in such situations. I doubt that they ever have been numerous in the bottomland woods; lack of rocks for shelter, and periodic flooding are unfavorable factors. In the Kaw flood of June and July, 1951, for instance, the entire valley was inundated, and in smaller tributary valleys such as that of the Wakarusa, flooding is frequent at the season when skinks are incubating their eggs. The uplands, formerly prairie, now are used partly for culti- vated crops and partly for pasture. The soil is poor and rocky, and now heavily eroded. The pastures mostly have a weedy type of vegetation indicative of overgrazing. Five-Hned skinks are absent from most of this upland. The steep slopes from the upland to the valley floor are now mostly wooded, and the population of skinks is chiefly in this band of woodland. Some of the hillsides that have relatively gentle slopes are treeless and are used for pasture, or are even under 3S UxrvERSiTY OF Kansas Publs., Mus. Nat. Hist. cultivation. Where second growth forest is present its aspect difiFers depending upon slope, exposure, and past treatment. Osage orange and honey locust are aggressive invaders on some dry hillside pas- tures, and in this type of woods the skinks are scarce or absent. Some hillside areas, especially on moist north slopes have thick second- growth woods, in which elm is usually the principal tree, with sev- eral oaks and hickories, walnut, hackberry, coffee tree, locust and osage orange, and with a dense understory vegetation of dogwood, gooseberry and coralberry, with vine tangles of grape, poison oak, and greenbrier. Such woodlands provide little food for livestock, and are often fenced off from adjacent pastures. The shading creates conditions unfavorable for skinks and they are relatively scarce in the denser woods. They are much more numerous in woodlands that are fenced in with pastures heavily grazed by cattle or horses, with understory vegetation kept cropped back, and with more open ground and patches of sunlight. However, they are absent or scarce in woods that have been subjected over periods of years to browsing, by sheep or goats, so heavily that hardly any herbaceous vegetation remains and so heavily that the soil is packed from trampling. Along the upper slopes, especially about heads of gullies, in areas strewn with flat rocks, in fairly open mixed woods, with some decaying wood on the ground, habitat conditions are most nearly optimum for the skinks. Artificial habitat features, such as rock piles, stone walls, wood piles, rail fences, or old deserted buildings and sheds, with loose boards lying about on the ground may support unusually high concentrations of skinks when the sur- rounding habitat is favorable. Stxjdy Areas The University of Kansas Natural History Reservation where most of the field work for this study was done, has been described in a recent publication (Fitch 1952:8). While records were ob- tained from scattered points throughout the 590-acre Reservation and elsewhere in northeastern Kansas, field study of this sldnk was concentrated on four relatively small areas totalling only about ten acres in extent (Figure 26). These areas were selected on the basis of abundance and availability of the skinks, and of variety of habitat conditions represented. One of these sites was a deserted quarry on a southward project- ing spur of the plateau-like cuesta top, where the upper layers of the Oread limestone are prominently exposed. In the course of operations, begun about 1937, the area was denuded of trees and Life History and Ecology of Five-lined Skink 39 shrubs, and the upper layers of Hmestone were removed from a strip about 50 feet wide and more than 100 yards long. The exposed out- crop presented a vertical rock face five to ten feet high, with south and southeast exposure. Numerous jagged seams and fissures in the rock hastened its disintegration. Quarrying had been discon- tinued several years before the present study was begun in 1948. At that time there were talus-like accumulations of rock and soil several feet wide along the base of the rock face, supporting a luxuriant pioneer vegetation especially, sweet clover, stickleaf, rag- weed and elm seedlings. The habitat conditions provided by the exposed rock outcrop at the border of woods and open land, proved unusually favorable for reptiles in general, and it was one of the most productive sites on the Reservation for Sonoran skinks, collared lizards, racerunners, ring-necked snakes, blue-racers, bull snakes, pilot blacksnakes, scar- let king snakes, slender tantillas, copperheads, and timber rattle- snakes. For the five-lined skink, however, this disturbed area was marginal, and supported only a sparse population. Several decay- ing two-inch boards were preferred hiding places where the skinks were found most frequently, and remains of collapsed rock walls, one in the center of the area and one at the edge of the woods, were also occupied. Skinks may have tended to wander away to more favorable situations or may have been more subject to predation than those elsewhere, since the incidence of recaptures was rela- tively low. Most of the records from this general area were from a ledge in adjacent woods rather than from the quarry itself. Another site was a rock fill in a ravine below a pond made in 1937. This rock fill was 70 feet long, up to 30 feet wide, and three feet deep. East and north of the rock pile was a grassy dike, and be- yond it the pond. On the west open grassland extended approxi- mately 200 feet to the edge of the woods, with a diversion ditch at its border. On the south end, the rock pile was adjacent to wood- land at the base of a steep slope with north exposure. On this slope the dense stand of second growth oak and hickory with an al- most continuous leaf canopy was a poor habitat. The rock pile was thus partly isolated and surrounded by areas that were either unin- habitable to the skinks or supported only sparse populations of them. By 1948 the rock pile was partly covered by grape vines. Dead leaves and other debris had accumulated in the deeper interstices between the rocks. Spiders, beetles, snails and other small animals were extremely numerous in the vicinity of the rock pile and pro- vided an abundant food supply. A large sycamore on the west side 40 Unr'ersity of Kansas Publs., Mus. Nat. Hist. of the rocks provided some afternoon shade. This rock pile pro- vided shelter for reptiles other than the five-lined skink — especially the garter snake, water snake, copperhead, and brown skink. Another area of about two and a fourth acres ("Skink Woods," Fig- ure 21 ) was the one most productive of skinks. It is a wooded upper slope adjacent to a hilltop pasture. Along the hilltop rim the upper stratum of the Oread limestone presents a rock face as much as four feet high at the north end, but less exposed at the south end where it was partly covered by deposited soil. Approximately 100 feet down the slope a second outcropping is present, with many loose rocks and boulders throughout the whole area. Soil is light and loamy. The slope has a west exposure. The stand of trees is fairly open, with several large elms, walnuts, and yellow oaks, and occa- sional hackberries, ailanthus and red haws. This area was included in a narrow strip of woodland fenced about 1940 as a runway con- necting a hilltop pasture with a valley pasture where water was available at a time when both pastures were heavily grazed by horses and cattle. As a result of trampling, browsing and grazing by livestock, understory vegetation of this area presented a difiFerent aspect from that in most other parts of the woodland. Saplings of the dominant tree species and shrubs, notably dogwood, gooseberry and crabapple, were relatively scarce. Herbaceous vegetation, es- pecially muhly grass, was conspicuous. By 1953 in the fifth growing season after livestock were removed, the area still contrasted with other parts of- the woodland in sparseness of shrubby vegetation. Old stock trails were still discernible, and some sheet erosion and gullying had occurred. The effect of livestock in holding back woody undergrowth seemed to be an important factor in improving the habitat as the skinks were much scarcer in adjacent woodlands on either side that were similar in species composition, size, and numbers of the larger trees, but different in having much thicker underbrush. These adjacent woodlands were not entirely com- parable, however, because they had more north-facing exposures. Reptile associates in the Skink Woods area include the brown skink, Sonoran skink, glass-snake, worm snake, ring-necked snake, blue-racer, garter snake, pilot blacksnake, copperhead and timber rattlesnake, but only the worm snake and ring-necked snake were abundant. Rat Woods, an area of approximately four acres, was like Skink Woods, formerly the upper part of a connecting strip between hill- top and valley pastures and was altered by the effect of concen- trated trampling and browsing by livestock. It is V-shaped, with Life History and Ecology of Five-lined Skink 41 the apex at the north end, and the slope exposures southwest and southeast. The area is bisected from north to south by a small gully, and remains of an old rock wall. To the east of this gully the lower outcrop is prominent but west of the gully, it is but little developed. As compared with other wooded areas, this one was relatively dry. Trees, and other vegetation in general, are some- what more xeric in aspect than are those in Skink Woods. Along the upper ledge are elms and hackberries, with many thick clumps of fragrant sumac. The trees are mainly elm, walnut, honey locust, and osage orange with hardly any oaks or hickories and, with shrubby undergrowth of dogwood, gooseberry, and coralberry sparser than in adjacent woodlands. Herbaceous vegetation con- sists largely of muhly grass, geum, and avens. On the hilltop edge above the ledge are many flat rocks of varying sizes, and the slope is thickly strewn with rocks, some of the larger ones deeply em- bedded in the soil. The population of five-lined skinks was rela- tively sparser than in Skink Woods. Other reptiles including the Sonoran skink, racerunner, glass-snake, worm snake, ring-necked snake, blue-racer, bull snake, pilot blacksnake, garter snake, scarlet king snake, slender tantilla, and copperhead, were more numerous in this area than in most other parts of the Reservation. The com- paratively scarce prairie skink was found only in this area, and the scarlet king snake and slender tantilla were found only here and at the quarry. The Annual Cycle of Reproduction and Growth Seasonal Occurrence Collectors and other observers have often noted that reptiles, in general, are not found in equal abundance throughout the entire season of their activity. Many kinds are most in evidence within a period of weeks after emergence from hibernation, which cor- responds with the time of breeding and later they become much scarcer. In skinks of the genus Eumeces this tendency is perhaps even more pronounced than in most other kinds of reptiles. By midsummer or considerably earlier their period of greatest activity is passed, and in some kinds, adults, or individuals of any size can rarely be found in the latter half of the growing season, even by a skilled collector familiar with their habitats and habits. Thus, Taylor (1936:5) in the preface of his revision of Eumeces, describ- ing the difiiculties involved in assembling needed series of the many Mexican species by collecting on summer field trips, wrote: "In 1934 in western Mexico ... I met with most dishearten- 42 Unrtrsity of Kansas Publs., Mus. Nat. Hist. ing results . . . (altliough more tlian 1500 specimens were collected) only a single specimen of Eumeces was taken. Hobart Smith, in 1934, accompanied by David Dunkle, made a journey into northwestern Mexico . . . and while generally successful, likewise obtained only a single specimen of Eumeces." FEB. MAR. APR MAY JUNE JULY AUG SEPT OCT NOV SEASONAL INCIDENCE OF CAPTURE RECORDS Fig. 7. Seasonal occurrence of five-lined skinks, based on data collected in 1949, 1950, 1951, and 1952; adult males and adult females are taken in greatest numbers in May, and in progressively smaller numbers through the summer and autumn; yearlings are found in increasing numbers through March, April, May, and June, then in decreasing numbers through the summer and autumn. In the present study the tendency of E. fasciatus to concentrate its surface activity in early spring was clearly shown. In unseason- ably warm weather in early spring, even in February in one in- stance, individual skinks have been found active on the surface or beneath flat rocks warmed by the sun; but general emergence ordinarily does not occur until sometime in April, depending on the weather. Unless the weather is much warmer than the sea- sonal norm, the skinks spend much of April in a torpid condition, either not becoming fully active until late in the month, or lapsing into torpidity with the return of cool weather after their first emergence from hibernation. During warm periods in April, Life History and Ecology of Five-lined Skink 43 however, activity is at or near its annual maximum for all in- dividuals regardless of sex or age. In May, with the advent of much warmer weather, daytime tem- peratures are usually high enough for the skinks to be active. Adult males travel about more actively and persistently than females or young, and as a result they are found so much more frequently that the numbers taken approximate those for adult females and young combined. Many of the adult males recorded in May were taken in funnel traps or pitfalls. Active males in the open were difficult to catch, and a high percentage of them escaped. To the casual collector or observer, these skinks are much more in evidence in May than at any other time of year, and most of those seen are adult males. By June, the numbers of skinks seen in the open de- cline abruptly. The adult males become relatively scarce, with reduction from more than half to about one-sixth of the total, and the young, about half-grown at that season, make up approximately half of the total. The adult females make up approximately one- third of the total June sample, but few of them were found active on the ground surface. Most were found in nest burrows beneath flat rocks. Under such conditions they tended to be sluggish in behavior, and were caught much more easily than were males and young. July was characterized by progressive decrease in the num- bers of adult males, adult females, and second year young, whereby the numbers of each group were little more than half of those for June; and by appearance of a new crop of hatchlings which made up about one-third of the month's sample. Hatchlings first appeared from early July to late July in different years; few were recorded in July in some years. Females were much less commonly found in nests in July than in June because many nesting attempts were terminated before the beginning of July or early in the month, and probably because those that remained were often more deeply buried and better concealed. By August the adult males, and the second year young (by then approaching adult size) were found in still smaller numbers, but the number of hatchlings and of adult females approximated those recorded in July. In the females there is evidently some resumption of activity after the incubation period is terminated. The females are then hungry and sometimes emaci- ated, weighing less, on the average, than the year-old young of shorter snout-vent length. The numbers of hatchlings are aug- mented through early August in some years, as late broods continue to hatch. By early September few skinks except hatchlings are to be found, and activity continues to wane throughout the month. 44 UxrVERSITY OF IC\NSAS PUBLS., MuS. NaT. HiST. In October skinks of any age or sex group are a rarity, even though temperature is about the optimum for their activity. Little is known concerning where and how they spend the fall months. Probably they are not actually dormant, but retreat underground where temperature is moderate and humidity is high. Individuals kept in captivity at this season were listless showing but little in- clination to feed. The only five-lined skink taken on the Reserva- tion in November was found in a funnel trap after a rain at the end of a long drought. It may have been attracted to the surface by moisture. The following table shows the dates on which various events of the annual cycle were observed in each of five different years. Owing to the secretive habits of the skinks, these events generally were not observed until somewhat after their earliest occurrence in any one season. The lag was greater in some instances than in others. Table 3. Phenology of the Annual Cycle in FrvE Different Years. 19i9 1950 1951 1952 1953 Earliest emergence from hit)ernation General emergence from hibernation Breeding coloration appearing in males Peak of breeding season Females starting nest burrows . . Last appearance of gravid females Earliest appearance of eggs . . . . Earliest appearance of hatohlings Latest hatching date Latest fall record Mar. 30 May 3 May 26 June 10 June 10 July 5 July 15 Oct. 15 Apr. 7 Apr. 15 May 12 May 24 June 17 June 13 Julv 15 Aug. 8 Sept. 19 Mar. 24 Apr. 14 Apr. 25 May 16 May 19 June 29 June 24 July 23 Aug. 8 Sept. 26 Mar. 29 Apr. 17 Apr. 28 May 10 May 19 June 9 June 22 July 3 July 14 Nov. 9 Mar. 20 IVIar. 27 Apr. 16 May 7 May 24 June 16 July 13 Oct. 12 Sexual Cycles and Behavior Reynolds (1943:370 and 1947:191) studied the histological and gross seasonal changes in the reproductive organs of the adult male Eiimeces fasciatus. There is a well defined annual cycle. "Early seasonal increase in seminiferous epithelial heights and in diameter of lumina and tubules reached a maximum in April followed by regression reaching complete involution by August. Late seasonal revival of activity results, by November, in size of testicular ele- ments comparable to those seen in January. Primary spermatocytes predominate in the germinal epithelium in January, secondary Life History and Ecology of Five-lined Skink 45 spermatocytes and spermatids in February, with spermatids and metamorphosing sperm dominating from March until late June when the germinal material of the current season is exhausted." Fifty- three adult males were used as a basis for his study. These were of diverse origins from Arkansas, Florida, Missouri, Tennessee, and Indiana. Since sexual cycles in such widely ranging species tend to be synchronized with local phenology, and change somewhat from one region to another, the seasonal cycle may have been some- what obscured by the diverse origins of the material. The Florida specimens may have been of the species E. inexpectatus. Appar- ently Reynolds' experimental skinks were kept in captivity for vary- ing lengths of time before their reproductive organs were examined. The normal cycle would almost certainly be altered in captivity, especially in skinks kept at high temperatures during the time that they would normally be hibernating. The seasonal change in gross appearance of the testes is not great. In the breeding season the testes are slightly enlarged and are firm and engorged, with pinkish or orange tinge. In immature males, and adults that are not in breeding condition, the testes are smaller, attenuate, paler colored, and flaccid. Sizes of testes in some males killed in the breeding season are recorded in Table 4. Table 4. Sizes of Testes in Spring and Early Summer Mature and Juvenal Males. IN Sexually Date Snout-vent length in mm. Sizes of testes in mm. Age class Mav 6, 1951 76 77 74 74 66 65 64 45 40 65 67 75 70 51 7.0 X 4.0 5.0 X 2.8 6.2 X 3.2 5.5 X 3.0 5.0 X 2.8 4.2 X 3.2 5.3 X 3.1 2.5 X 1.0 1.5 X .3 5.0 X 2.5 4.0 X 1.8 4.0 X 2.0 3.5 X 1.8 2.0 X .5 old adult May 20, 1951 May 20, 1951 Mav 20, 1951 old adult old adult old adult Mav 20, 1951 young adult young adult young adult juvenile juvenile young adult young adult old adult Mav 20, 1951 Mav 20, 1951 Mav 20, 1951 Mav 20, 1951 June 3, 1951 June 10, 1951 June 25, 1951 June 25, 1951 young adult juvenile June 25, 1951 From the time of emergence in spring, males show some tendency to seek out females, and frequently a pair may be found together under the same rock, weeks before the onset of the breeding season. There is no satisfactory evidence that such associations have any 46 University of Kansas Publs., Mus. Nat. Hist. permanence. At the time of emergence from hibernation the males rarely have even a trace of reddish coloration on their heads, and more than a month normally elapses before attainment of breeding coloration. Each year that observations were made activity' of the skinks was interrupted by cold weather in April, so that the lizards were fully active for only part of the time between their earliest emergence and their attainment of breeding condition five to eight weeks later. The reddish suflFusion of the breeding season, hardly showing in the first few weeks after emergence, appears suddenly within a few days in all adult males of the population. The best indication of the time necessary to attain breeding condition was provided by an adult male whose hibernation was interrupted on December 15 by bringing him into a warm room where he was kept at 80° F. or more in the daytime, and approximately 70° F. at night. Thirteen days later, on December 28, the male had developed a noticeable reddish suffusion. On January 3, nineteen days after hibernation terminated, the suffusion was near its maximum. \\%en an adult female was placed with the male on this date, he showed sexual interest but the courtship was not consummated. On January 6, the 22nd day, the male's colors had reached their maximum, and when the female was placed with him, pursuit and copulation occurred promptly. In the spring of 1952, the first skink of the season was found on March 29, still only partly activated, and under a large flat rock. Skinks were not caught or seen in any numbers until April 17, how- ever, and general emergence probably occurred only a day or tAvo earlier than this. On May 10, 1952, breeding activity was estimated to be at its peak. By May 28, the reddish suffusion was conspicu- ously faded in several males taken. By June 10 it was no longer discernible. In the immature female the oviducts are small and threadlike, and the ovaries have grapelike clusters of pale whitish eggs, which are minute, often less than .5 mm. in diameter (Figure 8A). In sexually mature females ova enlarge rapidly after emergence from hibernation in the spring. While eggs are still in the ovary, they are approximately spherical. In late April and early May the de- veloping ova enlarge rapidly. Approximate average sizes (dimen- sions in mm.) of developing ovarian ova in each of 22 mature females on different dates were as follows: April 17, 1949: 2.6, 2.3, 2.2, 2.2, 1.9, 1.9; April 18, 1949: 2.2, 1.9, 1.8, 1.1, 1.1; April 24, 1949: 4.6, 3.2, 2.5, 2.3; May 6, 1951: 2.5, 2.3; May 20, 1951: 7.0, 6.2; May 25, 1951: 8.0; June 3, 1951: 6.0, 5.5. Life History and Ecology of Five-lined Skink 47 The two females containing ovarian eggs on June 3, 1951, were retarded individuals, taken along with several others that had al- ready ovulated. Copulation takes place in early May before the ova have grown to their full size. In the following weeks both the ova and the oviducts enlarge rapidly. Upon passing into the ovi- ducts, the ova assume an oval shape and are approximately 9 by 6 mm. before the albumen and shell are added. Deposition of a clutch of eggs probably extends over only a day or two at most, as clutches appear abruptly in the nest cavities. On only a few oc- casions were the females found in nest cavities with their clutches partly laid. Fig. 8. Adult female skinks with ventral body walls removed to show re- productive organs. A. Condition in April shortly before the breeding season; the ovary (O) is still small and elongate, with the small ova forming a grape- like cluster; right ovary removed to expose the small bandhke oviduct (OD) beneath it. B. Condition in late May shortly before ovulation; the greatly enlarged ovaries are removed to expose the oviducts (OD) now enlarged and convoluted for reception of the ova. C. Same stage as B, with mature ova ( O ) fiUing most of the body cavity and conceahng other internal organs, I — intestine; L — hver; approximately natiiral size. Sexual behavior is for the most part limited to a short period of weeks in spring. In an average year in the area of the study the first two weeks of May would include the peak and the greater part 48 University of Kansas Publs., Mus. Nat. Hist. of the breeding season. The "courtship," such as it is, and mating have been described by many observers. However none of the pubhshed accounts seems to include all the essential features in their usual sequence as observed in the present study. It has been brought out by the studies of Noble and Bradley (1933: 94), Noble and Teale (1930: 54) and Schmidt (1933: 71-76) that the sexual behavior of lizards has phylogenetic significance. Certain basic patterns in mating behavior are characteristic of saurian families, other traits are characteristic of genera, while certain details may be characteristic of species, or perhaps even of subspecies. In the breeding season the adult male directs the greater part of his activities to a search for females, and finds them by both sight and scent. Observations on searching males suggest that they trail females by scent to some extent, or at least detect their presence in the general vicinity by this means. Upon discovering a female, the male pursues her with vigor and determination unless the tem- perature is too low, or unless he is not at the height of breeding condition. The female makes no positive response but reacts to the male's presence by fleeing, either frantically or perfunctorily, but if she is physiologically ready to breed the reaction is usually somewhat intermediate between these extremes. The first reaction of the male as he approaches the female is to touch her with his tongue, apparently receiving olfactory stimuli which are essential to the mating pattern. Rushing in pursuit of the female he then attempts to seize her in his jaws. Most often a preliminary grasp is secured on the female's tail. The female may resist vigorously, wriggling and clawing, turning upon the male to bite or to threaten with her gaping jaws. At the first opportunity the male deftly shifts his grip from the female's tail or hindquarters to a more anterior position, which may be as far forward as the forelimbs or may be as much as an inch behind them, a little to one side of the mid-dorsal line. The male secures his hold by pinching loose skin into a small fold. Having gained this position the male is more or less out of reach of the female's jaws, and after a brief struggle both rest quietly except for their rapid breathing, usually for a minute or more, the ventral surface of the male resting on the female's dorsal surface. The male suddenly thrusts his tail beneath that of the female. His hind leg then rests over the base of her tail and the right angle formed by the laterally projecting hind leg and the tail in each lizard aids to guide their hindquarters into position so that cloacal contact is established. Copulation then begins im- mediately. The male's body may be bent in a semicircle, to one PLATE 1 Fig. 1. Habitat of Eitmeccs fasciatus near the center of the "Skink Woods" study area on the University of Kansas Natural History Reserva- tion, a glade with loose rocks that were used as nesting sites and shelter by many five-hned skinks. ^ -tm^ '^ ;?V-*« Fig. 2. A log on rocky slope in open woods with sparse undergrowth, fifty feet from center of glade shown in Fig. 1. The trees are mostly oaks {Quercus Muehlcnhcrgii) . The decaying log in middle foreground is much frequented by the skinks as a shelter and source of insect food. PLATE 2 Fig. 1. Old adult male, year-old \()uiig and hatchling in Jul\-, show- ing differences in size and pattern. '-JT. i:. ¥ ■. .^ 1 II.. 2. Adull li malt skiuk in a natural ni-st, with her clutch of eggs late in incubation. 1'he nest ca\ity is e.\cavated in loose soil beneath a Hat rock, which was raised momentarily to expose the nest to \icw. -^-^v- oi Ki(.. .'3. 'Ilic same Iriiialc and ncsl, witli eggs in process ol lialeluiig. Life History and Ecology of Five-lined Skink 49 side of the female, or may be in an S-shaped loop, depending on whether or not the hemipenis employed is on the side opposite to that on which the female is grasped. Only one hemipenis is in- serted, but occasionally the other may be everted also. As copula- tion begins the male's hind leg, flexed over the female's tail base quivers, but otherwise there is hardly any movement during ap- proximately the first one-third of the copulatory period, and this phase may last for from one to three minutes. Then, abruptly, the male begins rhythmic, jerky flexions of the proximal portion of the tail, at the rate of approximately one per second. These tail movements are in a dorsoventral plane, and there is no perceptible movement of the body. Shortly after these movements cease, con- tact is broken usually at the initiative of the female, as she suddenly struggles to escape and is released either immediately or after a few seconds by the male. She then moves away, pressing her cloacal region against the ground. Her movements have become unhurried, with Httle or no attempt to avoid the male's attention. The male usually follows, either close behind, or straddling the female's tail or body. He may nip at her tail or body repeatedly, but without securing a grip. When the female pauses, he may come to rest with his chin or forequarters resting on her. Usually the association does not last more than a few minutes. Noble and Bradley (1933: 77) mention frequent homosexual matings between captive males. However, I observed no homo- sexual matings, either under natural conditions or in confinement. The pugnacious behavior of males that are in breeding condition ordinarily would prevent homosexual mating. Males in such weak- ened condition as to be unable to defend themselves effectively might evoke sexual attack, instead of the usual fighting response in other males. Although no actual experiments were performed in the present study in connection with the courtship and mating be- havior, accounts of some workers seem misleading. My own ob- servations indicate that the capacity for sex discrimination in this particular kind of lizard, and probably in others, has been under- rated. For example, it has been stated that the male rushes with open mouth at the neck of any other skink that happens to be around, and he identifies it as a male if it fights back, or as a female if it does not. On the contrary my observations indicate that sex recognition occurs almost as soon as the male is aware of another skink's presence. The red head of the breeding male is an excel- lent example of a social releaser in the sense that this term was used by Tinbergen (1948: 8). Like the red belly of the breeding 4—3559 50 UixrvERSiTY OF Kansas Publs., Mus. Nat. Hist. male stickleback, it facilitates sex recognition and evokes hostile behavior on the part of other males. Courtship, mating, and fight- ing reactions however, seem to be evoked by the interaction of a complex of social releasers. Whereas males and females are strik- ingly different in appearance in the breeding season, visual sex recognition is complicated by ontogenetic changes. The body stripes characteristic of the female pattern, become dull or even disappear in some old females, which then approximate the t\pical male pattern. On the other hand newly matured males in their first breeding season retain distinct body stripes of the female pat- tern. Their sex is evidenced mainly by their reddish facial suf- fusion, which is not quite so extensively developed as it is in older individuals. Also, in these newly matured males the temporal re- gion is not so swollen as it is in old males. The male whose dormancy was terminated in early winter by bringing him into a warm room causing him to assume breeding coloration and to breed some four months earlier than those under natural conditions has already been mentioned. By the time the regular breeding season arrived, this male had long since undergone sexual regression and retained no trace of the red suffusion. In this condition, placed in a terrarium with a mixed group of breed- ing adults, his social status was of unusual interest. He exhibited no interest in the females and was less pugnacious toward other males than were the individuals in breeding condition. Although he seemed somewhat more nervous and timid, his hostile behavior was not entirely suppressed, as from time to time he moved up to other males and bit them viciously. His color pattern resembled those of certain old adult females in which the body stripes have been suppressed, but the breeding males evidenced no uncertainty as to his sex and were uniformly hostile. Their reactions were not noticeably different toward him than they were toward breeding males. The importance of an olfactory stimulus as a social re- leaser in sexual behavior of lizards has not been appreciated, al- though Noble and Mason (1933: 10) did demonstrate its impor- tance in the behavior of the female toward her eggs. It is evident from published accounts, and from my own limited experience with fasciatus in parts of its range other than northeast- ern Kansas, that the phenology of the breeding cycle is subject to geographic variation, synchronizing with the somewhat different climatic conditions under which the species occurs. However, the difference is less than might be expected, in view of the species' extensive range. As a result of the early spring, and the warm Life History and Ecology of Five-lined Skink 51 summer climate in the southern states, dates of laying and hatch- ing may be several weeks advanced. On April 12, 1952, Dr. Wil- fred T. Neill showed me several live E. fasciatus, collected a few days before along the Trinity River in southeastern Texas, which appeared to be at the height of breeding condition. In northeast- ern Kansas on that date, general emergence had not yet occurred, and it was not until about May 10 that the population attained the peak of breeding condition. On May 8, 1948, near Burr Ferry, Vernon Parish, Louisiana, I caught an adult female in her nest burrow, and she contained eggs ready to be laid. Data with which Mr. Robert Gordon kindly provided me for specimens from southern Louisiana and southeastern Texas, in the Tulane University col- lection, indicate gravid females on June 4, 1952, and June 17, 1948 ( 3 ) , and females with their egg clutches on June 16, 1948, June 17, 1948, June 23, 1950; and hatching dates in captivity of July 19, 1949, July 19, 1950, July 25-26, 1949. These dates correspond well with those for specimens obtained in northeastern Kansas in the same years. In the northern part of the range, Ruthven (1911: 264) recorded that in the Saginaw Bay region, females taken on June 19 had eggs nearly ready to be laid, and after July 2 clutches were found frequently; young of the year were first observed on July 31. A Juvenal specimen in the University of Minnesota Natural History Museum, collected on August 11, 1938, at Dresser Junc- tion, Wisconsin, is 30/2 mm. in snout-vent length — approximately the size of juveniles in northeastern Kansas at the same season. Evans and Roecker (1951: 6) record hatching as occurring in the first week of September at Arden, Ontario, indicating that at the northern edge of the range hatching may be delayed as much as two months. With such delayed hatching, but little time remains for the young to grow before they are forced into retirement for hibernation. Fighting Territoriality in the usual sense is lacking in the five-lined skink, and could scarcely exist in an animal of its habits. To defend a definite area (territory) against intruders of its own species, the animal would have to detect such intruders promptly. The skink, however, is so secretive in habits that at any given time the indi- vidual is likely to be hiding and inactive, even when conditions are favorable for it to be in the open, and other individuals therefore can then wander onto its home range unopposed. Even when an individual is active, it lacks the ability to detect others, except within a radius which would encompass only a small fraction of 52 Unfv'ersity of Kansas Publs., Mus. Nat. Hist. the entire home range. The senses are inadequate to inform one Hzard of the presence of another until the two are only a few yards, or even a few inches apart. Usually the lizard is on the ground, where even small objects obstruct its view, and vision is probably effective for only a few yards. Hearing is probably effective for about the same radius in detecting animals of appro.\imately its own size. Scent is effective in detecting prey near at hand or on contact, but probably does not serve for detection of other lizards that are not in the immediate vicinity. Therefore, the area covered by one in the course of its normal activities may harbor many others, and individuals most of the time are unaware of the others on their home ranges. Under most circumstances these skinks behave toward each other with tolerance or indifference, but during the breeding season adult males become hostile, and fight on sight. Their reddish facial suf- fusion serves as a social releaser which elicits hostile behavior and facilitates sex recognition. As the breeding season wanes, the red- dish suffusion fades rapidly and male hostility, probably controlled by the same hormonal complex, is likewise suppressed. Hostile be- havior is rare in adult females or young at any time. Combats and pursuits have been observed most frequently the last week of April and especially in the first two weeks of May. At this season funnel traps set along rock ledges often caught two adult male skinks together. In almost every instance one of the two confined males was mutilated, with pieces of skin and flesh bitten from the tail and with chin, snout, and neck scarred; most serious wounds were usually in the sacral region or base of the tail or both. Often the wounds were so severe that the skink died in a short time in captivity and presumably others that were released died also. On April 28, 1949, a large adult male skink, chased by another, ran out in the middle of a trail and stopped. The pursuer stopped a few inches from it, then after a long pause, retreated in the direction from which it had come. For the five minutes that the pursued skink was watched, it lay motionless, partly hidden by dry leaves, evidently seeking to avoid further pursuit by con- cealment. I caught it without difficulty, and it seemed weak and dazed, as if injured in the fight. Its reddish suffusion was conspicuous, but not fully developed. On May 3, 1949, an adult male having bright red facial suffusion was ob- served searching persistently in ground litter; he was seen to find and pursue a female, and to copulate. A few minutes after mating was completed and the pair separated, a second male also searching in the vicinity came within sight of the first one. The two noticed each other at a distance of about 18 inches, indicating their awareness by their more alert, jerky movements, and spasmodic vibrating of their tails. The newcomer darted at the other, and for a moment Life History and Ecology of Five-lined Skink 53 they dodged and sparred. As one broke away to run, the other seized it by the tail. They were on an exposed tree root about an inch in diameter. The skink that was caught twisted its body around underneath the root and seized its adversary by the tail likewise, so that their linked bodies encircled the root, each squirming to disengage itself from the other's jaws. After a few seconds they did break apart, and then maneuvered briefly menacing each other at close quarters, but they gradually moved away and lost contact. On May 10, 1949, two adult males were seen to approach each other slowly, pausing for perhaps a minute when they were a httle more than one foot apart. Then one edged up to the other, and with a sudden lunge seized it by the head. The one seized broke away with a vigorous jerk, and promptly retaliated by biting the first one's head. After a few seconds of rapid sparring and thrashing, they broke apart, and one chased the other for several feet until it eluded further pursuit by dodging and hiding. Fig. 9. Adult male skinks fighting. A. Menacing approach. B. One has lunged and secured a grip on the other's side, holding it at right angle. The one caught is unable to flex its body and neck enough to secure a retaHatory grip on the attacker, and must break away by violent thrashing. On May 12, 1950, my attention was attracted by a rustling in dry leaves. Within a few inches of my foot two adult males were struggling fiercely with jaws interlocked. Sudden violent twisting and thrashing alternated with quiet periods of a few seconds duration, in which the lizards scarely moved except for heavy panting and twitching of their tails. After perhaps two minutes of fighting, one broke away and ran. For a distance of several feet it was closely pursued by the other, which, however, soon lost contact with it in the rough terrain and surface litter. On May 12, 1951, rustling in dry leaves attracted my attention to two large adult males fighting. For about fifteen minutes that they were observed, they struggled, with neither yielding ground, though they thrashed and rolled about over an area of several square feet. Sometimes they were disengaged for short intervals. Then facing in opposite directions, with their heads side by side, they would snap at each other's necks and shoulders (Figure 9). Part of the time both males had grips and were biting each other simultaneously, but more frequently one or the other had a temporary advantage. When one secured a grip it would strain to the utmost, biting as hard as it could and lunging for- ward with frequent short jerks, meanwhile striving to keep out of reach of the 54 University of Kansas Publs., Mus. Nat. Hist. other's jaws. The one caught in the attacker's grip was usually unable to flex its bocl\' shan^ly enough to reach its opponent at all, or could barely reach it at such an oblique angle that its jaws slipped off the smooth body. Sometimes the one held did succeed in catching the other's front foot. The one caught in the other's jaws always succeeded in tearing loose after a short time. In the interval while the attacker rested with jaws partly rela.xed, the victim had an opportunity to break away. Even when both were free, they did not obtain grips easily, but often made several unsuccessful lunges and bites, the jaws of each slipping off the finn, smooth sides of its opponent. Sometimes the attacker seized a fold of skin, or sometimes obtained a wide grip on its body. One which had obtained a grip sometimes rolled rapidly, spinning the other around and dashing it against the ground. As these rotations stopped, the victim might come to rest on its back in such a position that it was temporarily helpless, but always broke loose after further struggles. Neither showed any inclination to retreat until finally, when they were interlocked, rolling about almost at my feet, I attempted to catch them. Then they instantly disengaged and rushed away, and one escaped. The one caught had suffered but little injury in the fight. Numerous tooth marks were discernible as minute abrasions on the sur- face of the scales, but the bony dermal armor had not been perceptibly pene- trated during the prolonged and violent struggle. Eggs The eggs of Eumeces fasciatus are like diminutive chicken eggs in appearance. They are white when first laid, slightly translucent when held to the light. Within a day or two after they are laid, these eggs are soiled to a dull tan color, somewhat mottled, as a result of being rolled and dragged about in contact with the floor and wall of the nest burrow. Like the eggs of most other reptiles, those of Eumeces fasciatus have parchmentlike shells. These shells are thin and easily punctured. As incubation proceeds, the egg enlarges by gradual absorption of moisture and the somewhat elastic shell is stretched. An egg left in water for as much as a day does not gain in weight appreciably. Except for occasional abnormal ones, the eggs of any one clutch are notably uniform in size and shape at the time they are laid. As incubation proceeds, some eggs enlarge more rapidly than others, and attain larger ultimate size. Differences in shape also appear, some eggs becoming relatively elongate and thin, while others are thick and blunt. Some become distorted to asymmetrical shapes. In nests that have been deserted by the females, eggs of irregular shape are especially noticeable. It seems probable that the frequent shifting of the eggs by the female prevents unequal drying or stretching in different areas of the shell. Normal young were observed to hatch from grossly mis- shapen eggs. Under conditions of drought, the eggs may not en- large normally during the latter part of incubation, and may become indented or partly collapsed, and yet apparently normal young Life History and Ecology of Five-lined Skink 55 hatch from them. Both in the field, and in laboratory experiments, eggs were found to have remarkable tolerance for excess moisture. After heavy rains of summer thunderstorms, nests were sometimes found to have water trickling through them, and on occasion eggs were found to be partly submerged in water in the nest cavity. Ex- posed rocks at the heads of small gullies often were chosen by the female skinks as the shelter for their nests. In these situations the nests were exposed to run-oflF water. In July, 1951, especially, un- usually heavy precipitation resulted in the flooding of many nests. In some instances desertion by the females and destruction of the eggs seemed to have been caused by this flooding, even in the well- drained hillside situations where this study was made. The extent of tolerance to immersion in water probably depends on the stage of development, the temperature, the oxygen content of the water and other factors. One egg was fully immersed for ten minutes on July 20, 1951, then returned to a container with damp soil in the laboratory, where it seemed to develop normally. On July 30 it was opened and found to have a living fetus. Table 5. — Measurements in Millimeters and Weights in Grams of Eggs IN THE Same Clutch at Different Stages During Their Incubation, Showing Gradual Increase in Size. June 18 June 24 June 28 July 17 July 20 July 28 T3 OrSS CO « Average length (for 7) Average width (for 7) Typical length Typical width Maximum length Maximum width Minimum length Minimum width Average weight Typical weight Maximum weight Minimum weight 11.1 7.5 11.5 7.5 10.5 7.0 .4 12.5 9.9 .58= .63- 13.7 10.5 14.0 11.0 14.5 10.9 12.5 9.9 .82* 14.3 10.9 14.3 11.2 15.0 11.1 12.8 10.0 .90' .9 1.0 .7 14.7 11.1 14.8 11.0 15.5 11.4 13.5 10.5 1.0' 1.0 1.1 .7 Superior nximber indicates the number of individuals averaged. 56 University of Kansas Publs., Mus. Nat. Hist. which was a week short of hatching. On July 22 another egg of the same clutch was immersed and left in water for 23 hours. On July 30 it was ruptured in handling and found to contain a living fetus. On July 31 t\vo eggs were placed in a dish of water in a refrigerator. On August 5 they were removed and opened. Fetuses were dead and were not appreciably larger than the one of the same clutch in the egg opened on July 31. On August 5 two of the re- maining eggs of this clutch were placed in a Petri dish, partly immersed in water, with approximately one-fourth of the surface of each protruding and exposed to the air. Forty-eight hours later it was found that both eggs had hatched. Evaporation had reduced the water in the dish to an amount suffi- cient to cover only about the lower one-third of each egg. One hatchhng was missing, evidently having climbed out of the shallow dish and escaped to the floor. The other was found still standing in the water with its head protruding, and it was lively and in good condition. The remaining four eggs in this clutch, which had been kept in a container of damp earth, were also hatching on this date. On July 10, 1952, an egg in a late stage of incubation was immersed in water in the laborator\'. On July 14 when removed, it had fungus growing on it, and was found to have a dead fetus, nearly full-sized. The range of temperature tolerance of the embryo is wide, prob- ably comparable to that of the adult. Time required for incubation is dependent on temperature. Persistently wet and cloudy weather in the summer of 1951, keeping temperatures relatively low in nests, was a contributing cause to late hatching that summer. As com- pared with 1952, hatching was about one month delayed in 1951, but later emergence and breeding accounts for part of the differ- ence. The e.xtcnt to which low temperature may delay incubation was indicated by the effect of refrigeration on several experimental eggs, as recorded below. 1. July 8, 1952 Egg transferred from natural nest to jar of damp soil in refrigerator at 13.8°C. July 14, 1952 Seems to be in good condition. July 19, 1952 Partly collapsed. Weight and measurements same as on July 8; opened and found to contain a dead fetus. Snout- vent length 23 mm., forehead bulging, skin delicate and membranous. Colors somewhat dull, indicating that it was not quite fully developed, although it had attained the minimum hatching size. 2. July 10, 1952 Egg from natural nest (15.0x10.5 mm., .95 gm. ) put in refrigerator at 11.6°C. Control (14.5x10.6 mm., .8 gm.) from the same clutch kept in hatching medium in lab- oratory. July 13, 1952 Control egg hatching; refrigerated egg shows no indication of hatching. July 14, 1952 Experimental egg 15.8 x 10.8 mm., 1.0 gm., seems to be in good condition. Nest from which it was taken found to have all remaining eggs hatching today. Life History and Ecology of Five-lined Skink 57 July 19, 1952 Experimental egg 15.0 x 10.0 mm., 1.0 gm., removed from refrigerator and transferred to container in damp rotten wood in laboratory. Seems to be in good condition. July 23, 1952 Experimental egg found to be hatched this morning, and hatching must have occurred either in the night or late yesterday. Eggshell still damp and pliable. 3. July 10, 1952 Egg from natural nest ( 14.0 x 10.5 mm., .8 gm. ) put in refrigerator at 11.2°C., in container with damp decayed wood. Control egg (14.2x10.1 mm., .8 gm. ) from the same clutch kept in the same hatching medium in the laboratory. July 12, 1952 Nest from which experimental and control eggs were taken has started to hatch, and two hatchUngs were seen there. July 13, 1952 Control egg hatched. July 14, 1952 Experimental egg 14.2x10.1 mm., .8 gm., seems to be in good condition. Nest in field examined and all eggs were hatched, with only tliree of the hatchlings remaining, the others having dispersed. July 19, 1952 Experimental egg 14.0 x 10.0 mm., .95 gm., still appears to be in good condition; removed from refrigerator and kept in laboratory. July 23, 1952 Experimental egg found to be hatched, and hatchUng active although still in hiding beneath rotten wood. Probably it hatched early in the day of July 22; the empty shell is still moist. These experiments seem to show that, in the later stages of incuba- tion at least, lowering of temperature to 11° or 12° C. almost halts development of the fetus. Harm does not necessarily result, how- ever, and when again warmed to normal incubation temperatures, the eggs eventually hatch, the incubation period being lengthened by a time approximately equivalent to the interval of refrigeration. Under natural conditions the time required for incubation prob- ably varies within wide limits, controlled mainly by temperature. No two clutches receive the same amount of heat, as sites differ greatly in extent of insulation, and exposure to sunlight. Each year, earliest appearance of hatchlings is in a warm, sunny situation, and in cooler, well shaded places hatchlings appear somewhat later. Their incubation is evidently somewhat protracted, although later emergence from hibernation and later breeding of adults in these situations might also contribute to the delay. Widely different incubation periods have been recorded in the literature and the variation probably is not due to temperature alone. Noble and Mason (1933:4) recorded incubation periods for six females from the same locality, and evidently kept under the same laboratory conditions, as 47, 41, 36, 29, 29, and 27 days. Despite 58 Uxn-ERSiTY OF Kansas Publs., Mus. Nat. Hist. the wide difference in incubation time, all six clutches hatched within a 12-day period from July 5-17. It seems improbable that differences in temperature account for the 20-day disparity between maximum and minimum incubation time, in these females kept under similar conditions. Cagle (1940: 229) recorded an even shorter incubation period for one kept in the laboratory, which laid eggs on June 30; hatching occurred on July 23 and 24. Retention of eggs in the oviduct by females kept under unnatural conditions would partly explain their late laying and the short incubation period of their clutches. Such ability to retain eggs in the oviduct while their development proceeds would not be especially surprising in E. fasciatus since its congener E. lynxe of the highlands in south- ern Mexico is normally ovoviviparous (Hartweg, 1931:61; Taylor, 1936:171). Cagle did not determine incubation time for any of the natural nests found, but evidently in all of them laying occurred earlier than in the single female brought to the laboratory while still gravid. All the eggs in natural nests found by him were brought to the laboratory and most of them were hatched. Cagle remarked: "The fact that these 26 nests hatched within a period of nine days seemingly indicates that the egg laying period extends over not more than two weeks." In the present study no incubation periods so short as those re- corded by Noble and Mason, and Cagle, were observed. Incuba- tion times were recorded for clutches both in the laboratory and in the field, but for most of the clutches only approximate incubation periods were recorded. Failure to record the exact date of laying or of hatching, or both resulted from attempts to avoid frequent dis- turbance of females in their nests, which might have caused them to desert. One clutch of eggs laid in a terrarium probably on June 17, 1951 — possibly a day or two earlier — hatched on July 30, after an incubation of about 44 days. Another clutch, found in a terrarium on July 17, 1951, was estimated to have been laid about a week earlier, judging from the average length (11.8 mm.) and average weight ( .55 gm. ) of the eggs. These eggs hatched on August 9, a little more than three weeks after their discover>'. A clutch found in the field on June 25, 1951, evidently recently laid (average length 12 mm., weight .45 gm. ), hatched 41 days later, on August 5. Another clutch found in a ter- rarium on July 17, 1951, was estimated to have been laid ten days or two weeks before, as the average length was 12.7 mm. The eggs hatched on August 7, three weeks after their discovery. On June 25, 1951, an incomplete clutch of three eggs was found with a female which still had an unlaid egg. The three eggs probably had been laid the same day or the day before. They were kept in the laboratory and weighed and measured at intervals until July 28, 33 days after their discovery when both those that remained were accidentally punc- Life History and Ecology of Five-lined Skink. 59 tured and found to have nearly full term fetuses. In the field a nest which contained only a gravid female on June 24, 1951, had a clutch of eggs already mud stained and slightly enlarged on June 29. The most probable date of laying was June 26. On August 6 the eggs had all hatched but several young were still in the nest. Probably most hatched on August 5. The incubation time was hence approximately 40 days. On June 21, 1951, a natural nest was found with eggs already somewhat en- larged ( 12.5 X 8 mm. ) and mud stained. This nest was checked from time to time in the next few weeks, and after 39 days, on July 30, it was found that all the eggs had recently hatched, but six young were still in the nest cavity. Another nest was found on June 24, 1951, with the eggs already markedly enlarged ( 14 x 8 mm. ) indicating that laying must have been several days earher — probably well over a week. Hatching occurred approximately 34 days later, probably on July 28, since on July 26 there was no sign that hatch- ing was imminent, and on July 30 only the empty dried eggshells remained in the nest. The incubation time approximated six weeks for those nests with most complete records. Under wet and stormy weather conditions such as prevailed in 1951, this may have been the normal incubation period, but in warmer and drier years incubation time is shortened. In the five-lined skink each adult female normally produces one clutch of eggs annually. The size of the clutch produced is subject to individual variation, and is influenced by the age, size and con- dition of the female. Geographic variation in clutch size might also be expected. Data were obtained from breeding females killed and dissected, from counts of eggs found in natural nests in the field, and from clutches of eggs laid by females kept in captivity. For the total of 115 recorded clutches represented by the combined data from all these sources, the average number of eggs per clutch was 9.5. In many females dissected for the purpose of obtaining egg counts, ovulation had not yet occurred. The ovarian eggs present in each of these females included two main size groups, the larger ones in process of maturing and evidently destined for deposition in the current season, and minute, immature ones. A few of inter- mediate size were always present, however, resulting in uncertainty as to the size of the clutch being produced, especially when develop- ment had not proceeded far. Even when the larger eggs formed a fairly distinct size group, some usually were well below maximum size. Relatively high counts of clutches were obtained from these examinations of enlarged ovarian eggs. Evidently development frequently is arrested, and resorption may occur before ovulation. As a result the numbers of ovarian eggs developing are a poor indi- cation of actual clutch size. A series of gravid females were ob- 60 University of Kansas Publs., Mus. Nat. Hist. tained and examined after ovulation; the numbers of eggs in their oviducts probably indicates accurately the sizes of their clutches. Gravid females taken from their nest burrows and kept in the lab- oratory in containers with loose damp soil soon excavated new bur- rows and deposited clutches. Many natural nests were found in the field, and the egg counts obtained from them provided further data concerning clutch size. Although most of these clutches probably had their full complements of eggs, others certainly had sustained losses to predators, or to the females themselves, which may eat some of the eggs. Therefore the average number found is er- roneously low. Some of the natural nests found may have contained two or more clutches or parts of them, and the higher counts ob- tained from natural nests therefore are also questionable. For different sets of data on clutch size, numbers were as follows: Table 6. Size of Clutch. SoUKCE OF Sample Number of clutches Mean Standard deviation Maximum Minimum Early ovarian .... Late ovarian, uterine, or laid in captivity .... In natural nests . . 25 56 34 11.4±.46 9.16±.21 8.82±.32 2.28 1.85 1.85 20 15 16 5 4 4 On the average, larger females produce more eggs per clutch than do smaller females. Of 49 females for which measurements were recorded, and which had uterine or large ovarian eggs, 31 were 70 mm. or more in snout-vent length. These 31, mostly or entirely old adults, averaged 9.9 eggs per clutch, whereas 18 others that were 69 mm. or less in snout-vent length, and that must have been mainly or entirely newly matured adults in their first breeding season, averaged only 7.8 eggs per clutch. Smith (1946:350) states that in the northern part of the range of this skink there is some indication of decrease in size of clutches. This is not well shown by published records. For the southern states, most of the published records of clutch size are by authors who did not clearly distinguish between the three kinds of five- lined skinks, and there is some doubt as to which species is in- volved in each record. For 56 clutches reported upon from north of approximately latitude 37°, I obtain a slightly higher figure than for 11 clutches from south of this line. Geographic trends are, of Life History and Ecology of Five-lined Skink 61 course, obscured by individual variation, and perhaps by abnormal clutches produced by individuals kept in captivity. In Table 7, the figures marked with asterisks pertain to clutches that might have belonged to skinks of the species E. laticeps or E. inexpectatus since they were recorded in regions where laticeps and in some cases, inexpectatus also, occurs along with fasciatus. If these questionable clutches are excluded the remaining 55, definitely of fasciatus, average 8.48 eggs per clutch, whereas the 12 questionable clutches average 8.42. Both figures are close to the average of 8.82 ±: .32 eggs for the 34 natural nests recorded in the present study. For the total of 1661 eggs of 182 clutches, from the combined sample of all available records for clutches found in the present study or reported upon in the literature, the average egg number is 9.13. 80 E £ X t- o z UJ H70 UJ > o ^ 65 " ■- ■ • '■ -■' — ■ ...... • : f • ^' t • • : • ■ " I. -I.-- — , — .. ■ -^ « ■ • • • • i • ... , , , .. ■ , ^ 4 5 6 7 8 9 10 II 12 13 14 15 16 NUMBERS OF EGGS Fig. 10. Correlation between size of female and number of eggs in clutch; females in their first breeding season, mostly less than 72 mm. in snout-vent length, produce smaller clutches, on tlie average, than do larger and older fe- males, but there is extensive overlap. To sum up the available information on clutch size, the number of eggs is most typically 9, 10, or 11 and is more in large old fe- males, than in small, newly matured females. In natural nests, even in those that are successful, there is often some loss of eggs, which are eaten by predators, or by the female herself, with the 62 Unu'ersity of Kansas Publs., Mus. Nat. Hist. Table 7. — NtTMBERs of Eggs Per Clutch, Tr\tE of Occurrence, La^tng Dates and Hatching Dates, as Reported in the LiTERAixmE by Various Authors. ACTROR AUard Bishop .... Blancbard Burt Burt Burt Burt Burt Burt Cagle Conant. . . . Dunn Evans and Roecker. . . Fitoh (field notes) McCauley Noble and Mason. . . . Ruthven. . . Smith Numbers of eggs per clutch 8* 9* G; 11 9*. 9* 9*. 10* 8* 8* 6* 6* Average 9.16 in 26 ne-sts (6-15) 7,9.10. 11.13 12* 6.7 9 3; 20 in 3 other nests combined 2. .5. 5. 6,7,8,8 6.6.8,9. 11.13.14 Date recorded Mav, and June 18. 1926 June 2o to July 13. 1926 June 6, 1933 June 28, 1934 July 7, 1933 July 8, 1933 June - July July 22, 1947 Natural nest Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Laying date June 12, 1926 June 30 July 5 and 6 May 23,27.31; June 6,6,13,20 Hatching date July 23-24 July 27, July 27 Aug. 9 First week of Sept. August 30 July 5, 5. 6,7,9, 17 Ix)cality Northern Georgia Breathitt Co., Kentucky Tennessee Douglas Co., Kansas Arkansas Ashville, North Carolina Scott, Mississippi Emma, Georgia Elk River, Alabama ElkviHe. Illinois Ohio Arden, Ontario Vernon Parish, Louisiana Maryland Anderson Co., Kansas Michigan Ohio result that the egg counts made by various observers average some- what lower than the numbers actually produced. The loss during incubation cannot be measured readily since it is almost certainly sharply increased by the disturbance entailed in observing nests. Exposing nests, even momentarily, for observation, may result in compacting of the surrounding soil, desiccation, temporary or per- manent desertion by the female, and exposure to predation. Some indication of the incidence of loss during incubation might be ob- tained by counting and measuring the eggs in newly found nests and correlating numbers with size (indicating the length of time incubated). Life History and Ecology of Five-lined Skink 63 Brooding Lizards and snakes of several different families, are known to brood their clutches of eggs, although the great majority of ovi- parous forms do not do so. The brooding habit is perhaps best known in Eumeces fasciatus, and has been described by many authors. By far the most thorough account is that of Noble and Mason ( 1933 ) who observed and experimented upon seven females that laid clutches of eggs in captivity. These females, kept in sep- arate terraria, excavated nest burrows for reception of their clutches, and remained with them throughout the time of incuba- tion. There were three characteristic brooding postures; curved in a semicircle around the clutch, in an S-shaped figure extending among them, or lying straight, either over or among the eggs. The brooding females, taken quietly from their nests without disturbing them, were found to have temperatures averaging .4° C. higher tlian the nests. Evidently normal room temperatures were main- tained in the laboratory where the terraria were kept. The females occasionally left their nests, especially in late afternoon, to wander about the terraria, and to bask in sunlight. While basking, their temperatures averaged 2.7° C. higher than the nest temperatures. The authors suggested that an important function of the brooding female was to transfer warmth from absorbed sunlight to the eggs. They state: "In nature the importance of the mother's body heat in the incubation of the eggs probably varies greatly with the type of nesting site selected." They suggest that in clutches deposited in logs or stumps beneath a thin layer of bark exposed to direct sunlight the need for warming by the female would be less. My own observations do not support the idea that brooding by the female serves to hasten the development of the eggs. Both in the laboratory and in natural nests, clutches deserted by disturbed females hatched and the hatching was not unduly delayed. In the field, females were never observed to bask in the sun beside their nest burrows, and seemingly left them infrequently even to feed. When a female was caught in her nest burrow, her temperature nearly always approximated that of the surrounding earth with which she was in contact. The temperature in each nest depends primarily upon its situation. When the immediate vicinity of the nest receives direct sunlight, the eggs are warmed without the aid of the female, but when there is no sunlight the temperature is much lower. In order to maintain an appreciably higher nest tem- perature the female would have to make frequent trips to spots perhaps several feet or several yards away to find sunlight. Upon 64 University of Kansas Publs., Mus. Nat. Hist. returning to the nest, her body heat would be quickly dissipated into the eggs and the surroimding damp soil. She would need to shuttle back and forth almost continually between the nest and a spot exposed to sunshine. Cloudy weather often preventing the warming of the eggs by absorption of solar heat prevails during much of the incubation season, in the region of the present study, and probably to an even greater extent tliroughout the range as a whole. Noble and Mason state (op. cit.:9) that while in some non-brood- ing kinds of lizards the eggs are actually damaged by turning, the fe- male fasciatus frequently turns her eggs and moves the whole clutch about in the nest cavity. On returning to their nests the experimental females each invariably touched one or more eggs with their tongues as an olfactory test. Eggs of other kinds of lizards not of the genus Emneces, and shellacked eggs of fasciatus, or paraflBn models of them, ordinarily were discarded immediately after a single touch of the tougue. Eggs of other individuals of the species, and even the eggs of Eumeces laticeps were accepted as part of the brood. Any of the experimental females would quickly retrieve one of her eggs moved a short distance outside the nest cavity. Even if the whole clutch of eggs were scattered about, the female would, over a period of hours, gather the eggs and return them to the nest cavity. This movement of the eggs is accomplished by rolling or pushing them in a loop of the body or tail, or, less frequently, by grasping an egg in the jaws, lifting it, and gently placing it in a new position. Even if the females were blindfolded, they were still able to retrieve scattered eggs, but one in which the tongue tip was experimentally removed showed no further interest in its eggs, presumably having lost the capacity to recognize them by ol- factory test. In the present study clutches unattended by females were ob- served to sustain heavy losses, both in the laboratory and in the field, and no doubt the attending female performs important functions other than that of warming the eggs. In the damp or wet nest cavity, the eggs tend to adhere to each other and to the earth walls and floor, and become sealed to such surfaces as a result of partial drying, reducing the amount of surface exposed to the air and probably hindering respiration. An eggshell sealed in pro- longed contact with the soil tends to rot with the result that it is easily ruptured, and even if it is not broken there is the likelihood of fungi or microorganisms gaining entry and killing the embryo. In many of the eggs that were handled to obtain measurements and I Life History and Ecology of Five-lined Skink 65 weight, rupturing of shells occurred. The shells are tough and elastic to the extent that even when eggs being handled were accidentally dropped on the floor on several occasions, no damage to them resulted. However, slight friction on the shell was some- times sufficient to puncture one. Particles of sharp rock from the nest cavity may adhere to the shell, and result in rupturing, perhaps at weak spots where prolonged contact with the soil has caused deterioration. The female tends to keep her eggs in a compact cluster, shifting their position frequently so that no part of an eggshell adheres to its surroundings long enough for rotting to occur, and most of the surface of each egg is exposed to the air. Another important function of the brooding female seems to be that of altering the nest burrow and shifting the eggs so that the effects of unfavorable weather are minimized. The usual response to warm and dry weather is deepening of the nest burrow. A cavity originally in loose soil on the underside of a flat rock, having the eggs in contact with the rock surface, may be displaced downward. The female excavates loose soil from the floor of the burrow and packs it on the top and sides, until the eggs are two or even three inches underground, in a cavity different in position and shape from the original one, although derived from it by gradual stages. In many instances, however, no such response to drying was ob- served. Probably extensive alteration of the nest burrow no longer is possible after drying of the soil has progressed beyond a certain stage as these skinks are not strong diggers. In some nests that were examined frequently, with resulting desertions by the attend- ing females, the outlines of the cavities became indistinct and the soil around them became dry and packed. In heavy rains, when nest burrows are partly flooded, the females move the eggs to avoid their being submerged. The extent of the female's activity within the nest burrow is suggested by the glazed condition of the earth walls and floor, and by the mottled appearance which the eggshells soon acquire as a result of being slid and dragged about in the nest cavity. Still another important function of the female is to dampen the nest burrow to prevent desiccation of the eggs. Even in dry weather, females taken from nests almost invariably voided water in rela- tively large quantities. They drink dew or other available water, and may void the contents of the bladder to moisten the nest cavity, as on numerous occasions, when nests were exposed by raising 5—3559 66 Unr'ersity of Kansas Publs., Mus. Nat. Hist. flat rocks covering them, part of the chamber was seen to be re- cently watered, and distinctly moister than the surrounding soil. Noble and Mason (op. ciY.: 16-19) found that brooding females, in the laboratory, would vigorously defend their eggs against small enemies, including mice and lizards and the smaller kinds of snakes that were tested. The female watched alertly as the intruder ap- proached, and attempted to bite it if it came too near or touched an egg. The females failed to defend their nests against persons and against a large blacksnake; when confronted with such a threat, the female would nm from her nest cavity to hide. Cagle (1940: 228) stated that the brooding females found by him stayed in the nests even when the logs in which they were situated were chopped open with an ax, and that the skinks would attempt to bite when touched with tlie finger. In the present study, females whose nests were exposed never made any active attempt to defend them. Many darted away and hid as soon as they were exposed. In other instances, especially when the nest cavity was only partly exposed, from one side, the female cowered back against the inner wall, opening her mouth in threat if closely approached. If further molested she might then attempt to escape. In brooding females a tendency to sluggishness, and an aflBnity for the eggs delayed the usually speedy escape re- actions. The temperature of the female was ordinarily lower than it would have been in the open or on the underside of a flat rock, and this also tended to slow her reactions. Gravid females when exposed in nest cavities that still contain no eggs are similarly sluggish and reluctant to leave differing little or none in behavior from those that have laid their clutches. Usually the female was found with her body encircling the eggs, holding them together in a compact cluster in the center of the nest cavity. The eggs rest in contact with the loose soil on the floor of the cavity, with each other, and with the female's body in the case of the outer ones of the cluster. Normal brooding habits proved to be difficult to follow because the females were easily disturbed. In many instances those that had excavated nest burrows, but had not yet laid, deserted the nests after the disturbance involved in raising the sheltering rock. Fe- males that had already laid before discovery of their nests were somewhat less inclined to desert, but many did so. On numerous occasions, at the time of year when most females are gravid and are staying in nest burrows, I have discovered well formed nest burrows empty and seemingly deserted, with no female Life History and Ecology of Five-lined Skink 67 in evidence nearby. In some instances the female may have been out foraging or basking although she was not seen, and in other instances the female may have been killed by a predator or elimi- nated by some other accident. However, it seems that gravid fe- males frequently do desert their original nest burrows, for one cause or another, and excavate new ones. Such desertions were noted many times in the females observed on the study area, where the disturbance from my own activities in raising the sheltering rocks may have caused shifts, but it was probably not the sole motivation. One female shifted approximately 120 feet, to excavate her second nest burrow in a site that was damper and more heavily shaded than the first site. This was in the notably dry summer of 1952. Most of the favorite sites under flat rocks in open situations, that were used in 1950 and 1951, were not occupied in 1952 or 1953, although several females did use them for original excavations, which were deserted before laying, as drought conditions developed. In the summers of 1952 and 1953 nests were difficult to find, and those discovered were on the average deeper and better protected than those found in other years. As compared with other North American lizards in general, Eumeces fasciatus is notable for the relatively exposed and super- ficial situations chosen as nesting sites. However, it occurs in a climate of high humidity; in contrast, the great majority of our lizards live in arid climates where the eggs are in much greater danger of desiccation, and require better shelter to maintain the humidity at a sufficiently high level. Accounts in the literature and observations in the present study indicate that these skinks exercise a wide range of choice of nesting sites. Ruthven (1911:264) stated that in northern Michigan nests were usually in decaying logs; occasional nests were found in burrows in sand, but invariably de- caying wood was present in or around at least part of the nest. Blanchard (1922) mentions a nest in Tennessee that may have been made by either this species or £. laticeps "in a hollow in a dead willow tree about fifteen feet from the ground buried in the loose, damp, rotted wood." Noble and Mason (op. cit. :16) quote Blanchard ( in litt. ) that in northern Michigan fasciatus nests in logs that are exposed to sunlight. Conant (1951:31) stated that several clutches of eggs found in Ohio were an inch to six inches beneath the upper surface of the log or stump which sheltered them. Evans and Roecker (1951:70) record finding two incubating females in- side rotten pine logs, in Ontario. Cagle, studying this species near Elkville, Illinois, in oak-hickory woods, found 25 natural nests of 6S University of Kansas Publs., Mus. Nat. Hist. which three were in loose soil among the roots of a fallen tree, another was under loose bark of a log, and the remainder were all in cavities of partly decayed logs. Bishop (1926:119) recorded finding a female with a clutch of eggs beneath damp boards at Quicksand, Breathitt County, Kentucky. In the present study, more than one hundred natural nests were found, of which just one (containing two clutches of eggs) was in decaying wood beneath the bark of an old log. All other nests were beneath rocks. On the University of Kansas Natural History Reser\'ation, where most of the nests were found, the policy is not to tear apart decaying logs; therefore the nests probably present in such situations were not ordinarily found. On several occasions groups of hatchlings were seen on logs within which they probably had hatched. In the area of the study, however, decaying logs are scarce. The hardwood forests consist mostly of young trees that are second growth on cutover areas or pioneer on areas that were previously grassland. Because of frequent cutting there are few old mature trees, and logs have not accumulated on the forest floor. In northeastern Kansas, nesting in l6gs is comparatively rare. On wooded slopes and the edges of level hilltops, the flat limestone rocks that are often abundant provide preferred nesting sites. Even on collecting trips off the Reservation, where stumps and logs could be torn apart and searched, flat rocks were found to provide the main source of nesting sites. These nest rocks varied from less than an inch in thickness to nine inches or more, and from a few inches in diameter to three feet or more. Some were resting loosely on the surface of the soil and others were deeply sunken, on one side. Some were in situations exposing them to nearly the maximum amount of sunshine whereas others were in sites nearly always shaded. The varied character of the nesting sites chosen demonstrated a wide range of tolerance for temperature, moisture, and other factors, in the gravid and brooding female and in the developing embryo. As already mentioned. Noble and Mason {op. cit. -.9-10) noted that females would accept and brood the eggs of other individuals just as readily as their own, and several writers have reported gre- garious nesting habits, with two or more females occupying either the same nest cavity, or separate cavities that were in close prox- imity. For instance, Cagle wrote that among the small logs he found to contain nests, four logs each contained one nest, five each contained two nests, and two each contained three nests, while three other nests were found within an eight inch square area in loose Life History and Ecology of Five-lined Skink 69 soil among tree roots. McCauley (1939:93) in Maryland found three females brooding clutches of eggs, which totaled 20, and which were so near together that there was uncertainty as to which clutch certain eggs belonged in. The gregarious nesting habit may be of benefit in permitting maximum utilization of choice nesting sites, where such sites are in short supply in an environment otherwise favorable. Also, the gregarious tendencies make possible more continuous guarding of the eggs against such natural enemies as can be repulsed by the female, since each female occasionally interrupts her brooding to bask or forage. Many of the nests tliat I found were in close proximity to others. Often two nests, and sometimes even three, were found beneath the same rock, and sometimes a distance of only two or three inches intervened between the separate clutches. It seemed, however, that in almost every instance each female had excavated a separate nest chamber originally. In some instances adjacent nest chambers com- municated with each other. On July 13, 1948, a communal nest was discovered beneath loose bark of a decaying elm log. There were 22 eggs in the combined clutch, and there were two females in the vicinity. The bark was raised on several different days to examine the eggs, and one or both females always were found with the eggs. On June 10, 1949, at the pond rock pile, a flat rock was turned and an unusual nesting aggregation consisting of a minimum of eight females, and probably more than ten, was found. The nests were somewhat disturbed by movement of the rock. The ground beneath was honeycombed with tunnels connecting the flask-shaped nest cavities, which were in part open to the rock surface on their upper sides. Clutches of eggs numbered 13, 12, 11, 8, and 6 (the last attended by a female which appeared to be still distended with several more unlaid eggs ) . Of five otlier females taken, two had laid and three were still gravid. Of the five clutches, two had eggs noticeably larger than those in the otlier three, and with their shells mottled brown from adhering earth. These nest cavities were about half an inch deep and two to three inches wide. The females were released as soon as they had been examined. One female moved about over the nest areas exposed, and evinced interest in a lone egg which had become separated from the others. She moved up to it, standing high off the ground, with her head turned at right angles to her body as if preparing to push the egg forward in 70 University of Kansas Publs., Mus. Nat. Hist. the angle thus formed, and tested it with her tongue, but then she became alarmed and left the vicinity. The flat rock was lowered over the nests again with a minimum of disturbance. On July 9, 1949, the flat rock covering the nests was raised again. Most of the eggs had hatched. Two broods of hatchlings were still in their respective nest cavities, and one entire clutch had not begun to hatch although its incubation was nearly completed. Three eggs of Scincella laterale were found mixed with the Eiimeces eggs. One of these was opened to verify tlieir identity; the other two hatched a few days later in the laboratory. The following selected excerpts from my field notes, setting forth histories of several nests, so far as they were known, give some idea of the types of nesting sites chosen, the behavior of the females, and the hazards to which the eggs are exposed. No. 1. At comer of pond rock pile. June 21, 1951. Female escaped when rock was turned. One egg measured 12.5 X 8 mm., mud-stained. June 22, 1951. Nest not in evidence when rock was turned; digging into loose soil beneath to a depth of about an inch I exposed the eggs but did not dis- turb them further. July 23, 1951. When rock was turned, female did not attempt to escape, but withdrew to far comer of nest cavity; when caught she voided a large scat which seemed to consist mainly of Ceuthophilus remains. Largest eggs in the clutch were 18 x 10 mm. but two were noticeably smaller, and all were heavily coated with dried mud. July 30, 1951. Six young in the nest cavity, still not fully active; all of them were heavily coated with dried mud. No. 2. At hilltop ledge, under flat rock 13 x 10 x 1 inches, with one edge sunken in soil; exposed to sunshine for most of day. June 24, 1951. Female, snout-vent length 70 mm., tail 27-51, weight 5 gms. Nine eggs, one of which measured 14 x 8 mm. July 18, 1951. Nine eggs still in their original nest cavity, attended by the female; she escaped into crevice behind the rock. The eggs were in slightly damp soil, and in contact with the undersurface of the rock on their upper sides; one egg was 17 x 10 mm. July 26, 1951. Eggs caked with dried mud; still attended by female. July 30, 1951. Dry and empty eggshells in nest cavity, evidently all the eggs had hatched; no other trace of female nor of young; July 28th seems most probable hatching date — if, on the 27th, some of eggs almost certainly would have shown signs of hatching on the 26th when they were examined, and if on the 29th some stragglers almost surely would have remained at the nest on July 30. No. 3. In small gully, on lower slope in hickory woods, beneath rock 9x9x1 inches, shaded by trees on south side for much of the day, especially during latter part of morning. June 24, 1951. The gravid female was deep in nest burrow. Life History and Ecology of Five-lined Skink 71 June 29, 1951. When rock was lifted no trace of nest was visible except for slightly disturbed loose soil at the point where it had been. When some of this loose soil was cleared away, nest was revealed, with 11 eggs, mud- stained, approximately 12.5 x 8 mm. The female was cold and sluggish, and did not attempt to escape, but cowered in the back of the nest burrow, with jaws gaping; she was caught and marked. July 20, 1951. Eight eggs remaining in the nest — two were accidentally de- stroyed in moving them. These two were fertile and contained live em- bryos, one of which measured 29 mm. in over-all length. One of the remaining eggs was 16.5 x 10 mm. Female was present with the eggs. July 25, 1951. Eggs still present in the nest cavity; female not in evidence, but might have been concealed in comer of nest chamber as it was not dis- turbed. July 28, 1951. Female was again found with the eggs. One or more of the seven remaining eggs were punctured in moving them during their exami- nation. Eggs about 16 x 10 mm. August 3, 1951. Female was in nest with the eggs some of which are slightly indented from drying. August 6, 1951. When rock was turned, female darted out and ran to cover about ten feet away. The eggs had hatched but two young remained in the nest cavity, still rather slow and feeble in their movements and not yet fully active. When routed from cover a second time, the female ran back to the nest rock and took shelter beneath it. No. 4. On upper slope above ledge, under a rock 18 x 9 inches, in site shaded most of day; burrow nearly concealed beneath rock. June 24, 1951. Nest occupied by a gravid female, apparently ready to lay. June 30, 1951. Rock covering this nest has been undermined by a mole tun- nel, and many nearby rocks are undermined also. The eggs were almost certainly destroyed by the mole's timneling and may have been eaten by it, since no remains are in evidence. No. 5. At hilltop ledge beside old abandoned road, beneath flat rock nine inches in diameter and about VA inches thick, shaded for first half of morning and most of afternoon, but exposed to mid-day sunshine. June 29, 1951. Standing water in bottom of nest chamber VA inches below underside of the rock. Some of the eggs are more than half submerged. One egg is 14 x 8 mm. July 21, 1951. Entrance of abandoned nest burrow has been enlarged by running water channelled through in run-ofiF during and after heavy rains; shrivelled remains of eggs present at the bottom of the bvurow. No. 6. On grassy hilltop a few yards from ledge under flat rock, 9x6x2 inches. July 23, 1951. Large female (snout-vent length 75 mm.) with three eggs, 16 X 22 mm. July 27, 1951. Female escaped from nest cavity as rock was raised. Three eggs were still in the nest, and a young skink was partly emerged from one. A second egg not yet hatching was somewhat flaccid, 16 mm. long, heavily coated with dried mud. The third egg much shrivelled, was opened and found to have a dead fetus, perhaps a week short of hatching. 72 Uni\-ersity of Kansas Publs., Mus. Nat. Hist. July 28, 1951. The flat rock which formerly covered the nest cavity was found to have been raised and displaced, and no trace of the female, eggs or young remained. Of possible predators that might have moved the rock and destroyed the nest, skunk and opossum seemed the most hkely, but there was no definite clue as to the predator's identity. No. 7. Two feet northeast of pond rock pile, under rock about one foot square on upper surface with ma.\imum thickness of about eight inches, lying with upper side at 45-degree angle. The nest was under one edge, with approximately three inches of rock over it. The rock was exposed to sunshine throughout the day, except for grass shading its edges. July 23, 1951. When rock was turned, the female darted out of the nest ca\ity, but in her dash to escape she dropped into a near-by pitfall. When handled, she voided feces which contained the nearly intact shell of a skink egg. Six eggs present in the nest; one selected as typical was IIM x 8 mm. The eggs were slightly misshapen and might have been damaged from drying. July 26, 1951. When rock was raised, female darted out and escaped. The six eggs still remained in the nest. August 2, 1951. When rock was raised the female was not in evidence, and only three eggs could be found; they had fallen from the nest cavity to the bottom of the depression where the rock was imbedded and were somewhat dried and indented. No. 8. North slope, beneath rock appro.ximately 18 x 15 x 4 inches, at edge of small gully, where shaded most of the time including mid-day hours. July 20, 1951. Female attempted to escape from the nest. Four eggs visible in nest, one 15/2 x 10 mm. July 25, 1951. When rock was raised the female ran from the nest. July 27, 1951. When rock was raised the female was in the nest with the eggs; she ran and hid beneath a boulder five feet away. After a few minutes she emerged and ran 15 feet to a hickory sapling and climbed it. July 28, 1951. Female was not in the nest but the four eggs were still present. July 30, 1951. Female found dead and partly eaten by ants beside rock one foot from nest; eggs still present in the nest. July 31, 1951. Eggs still present in the nest. August 3, 1951. Eggs still present, including some deep in the nest cavity which apparently were overlooked previously. August 6, 1951. One much indented egg found outside the nest cavity was opened and found to contain a live fetus, seemingly fully developed and normal. The opened egg was placed on damp soil in a shady place near the nest, but two hours later the hatchling had been killed and partly eaten by swarms of ants. August 9, 1951. The remaining eggs had disappeared, evidently taken by a predator as no empty shells remained to indicate that the young had hatched. Hatchlings ' Cagle (1940:229 and 232) has graphically described and illus- trated the hatching of the five-lined skink, and numerous observa- tions in the present study have served to corroborate his description. The first indication that the time of hatching is at hand is a twitch- Life History and Ecology of Five-lined Skink 73 ing or jerking movement w^ithin the egg which continues until the shell is slit. According to Noble and Mason (1933:5) the shell is slit with the elongate premaxillary egg tooth which has its distal third bent forward nearly at right angles to its base. Some young remain for an hour or more with only the snout visible, however, once the head is extruded it is not again withdrawn unless the lizard is badly startled. The eyes are opened and blinked slowly, closed for a few minutes, and opened again. After the eyes have become adjusted, the fore-body emerges and the front legs are freed. In one clutch, observed by Cagle, hatching time for individual eggs varied from 45 minutes to five and three-fourths hours. If startled by visual or tactile stimuli, the little skink may lunge forward through the slit shell, with a sudden straightening of its body, and rush away for several inches. Its movements are slow, stiff and clumsy as compared with those of a skink that is a few days old and fully active. Hatching of a clutch ordinarily extends over 24 hours or more. Some of the young may be fully hatched and active before others from the same clutch have slit their eggshells. Eggs ready to hatch ordinarily weigh somewhat more than one gram, up to at least as much as 1.7 grams, but much of this weight is made up of water absorbed during incubation. The hatchlings usually weigh from .2 to .45 grams. For each of two eggshells recently vacated, that were washed and squeezed dry, weights were approximately .125 grams. HatchHngs of the same brood differ perceptibly in size with several per cent variation in total length, and weight. Some seem to be less fully developed than others. On July 8, 1952, hatching of the last young in a clutch was observed. Upon emergence, it differed in appearance from the others of the brood hatched a few hours earlier. The top of its head bulged slightly as in fetuses. The umbilicus was not yet closed, and the protruding yolk mass hindered the hatchling's movements and made crawling diflBcult. In order to progress it had to stand high off the ground to prevent its ventral surface from dragging. Protrusion of the yolk mass has been described in newly emerged hatchlings for the closely related E. anthracinus (Clausen, 1938:3-7) as well as in fasciatus. Cagle (loc. cit.) states that the mass of yolk is at first about 3 mm. in diameter, but is completely used at the end of the third day. A group of young retained by him, without food, died the sixth day after hatching, seemingly from starvation. Three of five recently hatched young were found by Cagle to have eaten ant pupae placed in a box with them on the preceding day, even though the skinks still retained the yolk masses. One hatchling of this group 74 UNTrvERSiTY OF Kansas Publs., Mus. Nat. Hist. ate its own tail that had been broken off in handhng. Cagle de- scribed a color change taking place during the first few hours after hatching; the ground color, dull greenish at first, darkens to an iridescent black, the pale stripes are altered from an original tan color to bronze, with a tinge of reddish on the head, and the ventral surface which is partially transparent showing the outlines of the internal organs at first, soon becomes opaque white. Contrary to the statement by Noble and Mason (1933:5) that in captivity the hatchlings seldom stayed together more than a few hours, litters of young fully active, a day or two after hatching were found in the nests with the females still looped around them on several occasions. On one such occasion, although the brood scat- tered immediately into surrounding vegetation where they hid, I succeeded in catching the female and six of the young, and put them all together in a nylon bag to carry them back to the labora- tory. Several hours after the bag had been placed on a table it was noticed that the family had again gathered into a compact cluster in the bag with the female's body looped around the young in the characteristic brooding position seen in those with young or eggs in their nest cavities. When hatching is complete, the female may leave before the young have dispersed. On August 5, 1950, a nest under observation was found to have all of the young or most of them still clustered in the cavity, but the female was not in evi- dence. The young were active, and immediately took alarm as the rock was raised exposing them. Almost instantly, they scattered and vanished. Subsequent search revealed five of the young, each poorly concealed in tufts of grass or under dry leaves or other ground litter at the edges of the depression where the rock had lain. Once hidden, these young were reluctant to run again and depended on concealment. Having once left the nest, the young probably do not return to it, as many nests examined within a few days after hatching were never found occupied either by females or young after their original dispersal. As soon as the dispersal occurs family ties are perma- nently severed. On July 19, 1950, a group of active hatchlings was observed moving about over a log, on what was probably the first day of activity away from the nest. The log was in the bottom of a steep-walled gully, where it had come to rest the night before. It had been an erect but dead and partly undermined snag on the edge of the gully, and was blown down that night in a violent thunderstorm. Most of the log was held clear of the rushing water in the bottom of the gully by projecting limbs. The little skinks Life History and Ecology of Five-lined Skink 75 were darting in and out of holes and crevices in the log, pausing fre- quently to bask. As many as four were in sight simultaneously, but probably the total included several more, as it was diflScult to keep track of individuals. An adult female, presumably the mother of the litter was also present, but she took no interest in the young, and they showed no evidence of dependence on her. On the con- trary, several times when one or another of the young happened to come near the female in the course of its wandering, and noticed her, it was seen to shy away in sudden alarm. I I I I I — I I I I I II I 70 1 — n — r I I I I I I I I I I I I 60 E ?50 X O LU H ^40 O 30 i° ° 1950 YOUNG 1952 YOUNG X r. 20 I I I I I I I I I II I I I I I I I I 10 20 30 10 20 30 10 20 30 10 20 30 10 20 30 APR. MAY JUNE JULY AUG. Fig. 11. Sizes on specific dates of young hatched in 1950 and 1952. Ap- proximate size ranges at different times of year, and differences in trend be- tween the two years are brought out. 76 Uxn-ERSiTY OF Kansas Publs., Mus. Nat. Hist. The young were much more active than the female. These and other young observed in the open were almost constantly in motion. Pauses to bask at any one spot were of only a few seconds duration. A certain log in Skink Woods evidently was the site of one or more successful skink nests each year that observ^ations were made, al- though a nest was actually found in it only in 1948. On July 26, 1950, recently hatched young were active on this log. Temperature was about 22° C. and the young were alternating frequently be- tween shade and sunshine to maintain their body temperature. Collectively they seemed to cover every square inch of the log sur- face, poking and probing into niches, crevices and insect borings. They had a tendency to seek out the highest points on the log as resting places. In moving about, foraging or sunning, the young often carry the tail arched high, and keep it in motion with slow squirming undula- tions. These undulations may be continued even when the lizard itself has come to rest momentarily. The movements of the tail together with its vivid blue color serve to attract attention to it. Such behavior has not been observed in adults or partly grown young. Jopson (1938:90) observed an instance in which two dogs cornered a young five-lined skink (either the present species or E. luticeps) but were distracted by the wriggling of its bright blue tail "either dropped by autotomy or knocked off' so that the skink itself was allowed to escape. On another occasion these same two dogs attacking an adult male skink, were not distracted by the wriggling but dull colored broken tail, and they killed the lizard. Growth The subject of growth in Eumeces was briefly discussed by Taylor (1936:66) in his revision of the genus. Sorting fairly large series of museum specimens into seeming age-size groups, Taylor con- cluded that skinks require as much as 9 or 10 years to attain adult size. For fasciattis, for instance, the snout-vent length of 65.7 mm. (small adult size) was considered typical of individuals in their ninth year of life, with yearly gain of only 6 or 7 mm. in length in the young. I have seen the original data on which this conclusion was based, and the age groupings, as assigned by Taylor, seemed plausible. However, in the light of present knowledge, it is certain that the seeming intervals between his assumed age groups would have disappeared with a still larger series of specimens. The eight or nine size groups that Taylor recognized as distinct annual age groups actually comprise only two age groups, each having such Life History and Ecology of Five-lined Skink 77 wide dispersion of individuals ( by retardation of some and accelera- tion of others ) that there is overlapping in size between them. Growth in reptiles is now much better understood. Many species have been studied by a variety of methods, including observation of growth in captives, recording of growth in marked individuals living under natural conditions, and sorting of large series into age-size groups. Two species of Eiimeces have been studied in some detail. Breckenridge (1943:601-602) marked all the individ- uals of septentrionalis that could be found in a small colony in Minnesota and he concluded from the growth recorded in several that were recaptured, that these skinks grow to mature size ( 65 mm. and larger) at the end of their second year of life and are ready to breed the following spring. Rodgers and Memmler (1943:61) plot- ted the size distribution of a large year-round collection of skiltonia- nus from near Berkeley, California. They found that in this species hatching occurs in July and August, hatchlings are about 25 mm. in snout-vent length, and grow to about 50 mm. by the time they are one year old, and to about 65 mm. at two years of age, but most of them breed at the end of their third year. Within the genus the species septentrionalis and skiltonianus belong to groups separate from each other and from that including fasciatus. While septen- trionalis and skiltonianus resemble each other in their growth pat- tern and in the time required to reach sexual maturity, fasciatus is notably different in its more rapid growth and the shorter time it requires to reach breeding maturity. This would scarcely be ex- pected, as all three are of similar size. Furthermore, skiltonianus in the region of Rodgers' and Memmler 's study has a longer growing season than fasciatus in northeastern Kansas, while septentrionalis in Minnesota has a growing season markedly shorter than either. It is noteworthy that each of these three skinks is the northernmost lizard in the section of the country where it occurs. In the present study growth was investigated by measuring and marking large numbers of young, many of which were recap- tured for subsequent records, and by sorting into age-size groups all available measurements. An understanding of the latter set of data was facilitated by correlating it with the growth records of marked individuals. Changes in the phenology of growth from year to year according to weather conditions were noted. As already indicated, hatching occurs from early July to mid- August in northeastern Kansas. Unseasonably cool weather with frequent rains may cause cumulative delay in breeding and incuba- tion so that hatching may average several weeks later than it does 78 University of Kansas Publs., Mus. Nat. Hist. in years with relatively warm and dry weather during the breeding season. Within any one year hatching time is concentrated, so that the majority of the young hatch within a period of two weeks, but microclimates in the situations where the nests are made may differ enough to cause this much spread. Individuals living on north slopes in thick woods, and receiving the minimum amount of sun- light may have their emergence from hibernation and attainment of breeding condition delayed. Later, nesting in the same situa- tions, they may have incubation of their clutches similarly delayed. Newly hatched young average just under an inch in snout-vent length (23-27 mm.) and weigh .2 to .45 grams. Most rapid growth occurs in the period of weeks following hatching. The growth rate during this late summer period cannot be well shown by comparing average size of series taken on successive dates, because each series is likely to include some newly hatched young. In 1949, a series of recently hatched young averaged 26.7 mm. on July 10. By August 26, average length in a series collected was 42.9 mm., indicating an average gain of at least .35 mm. per day. One that may be considered typical was marked on July 23, 1950, soon after hatching, and it had a snout-vent length of 26.5 mm. and weighed .25 grams. It was recaptured just a month later when it had grown to 36 mm. snout-vent length, and weighed .8 grams. Potential growth rate under favorable conditions is shown by the fact that some individuals have attained a snout-vent length of 50 mm. by the third week of August, thus approximately doubling their hatching length. A maximum growth rate of about .5 mm. per day is indicated for these accelerated individuals, but on the average, young are considerably less than 50 mm. in length even when they enter hibernation. At the other extreme, representing retarded growth, is an individual having a snout-vent length of only 34 mm. on May 1. It must have been approximately nine months old on that date, but of course had spent at least six months in hibernation. Even if it made rapid growth subsequently, this yearling could scarcely have attained by midsummer the pre-hibernation length of the most accelerated individuals. During the growing season following their first hibernation period, the young grow to small adult size in most instances. After emerging from a second hibernation they mature sexually and constitute an important part of the breeding population. Many of the skinks marked before their first hibernation, as hatchlings, when they were a few days or a few weeks old, were subsequently recaptured as well-grown yearlings or small adults, Life History and Ecology of Five-lined Skink 79 afiFording ample information as to the usual growth rate and the extremes of acceleration or retardation that occasionally occur. Rec- ords of selected individuals in this group of skinks, marked early in life and recaptured after a hibernation, are recorded below. Table 8. Records of iNDtviDUAL Skinks Marked as Hatchlings (Before THE First Hibernation) and Recaptured the Following Year. Rapid Rate of Early Growth Is Shown. Date Snout- vent length in mm. Tail length in mm. Weight in grams Remarks No. 1. Augusts, 1951 23M S014 .25 Had just hatehed when April 28, 1952 39 55 + J^ 1.3 first recorded; second June 7, 1952 48 69 + 1 capture was made soon after emergence from hibernation. All three captures within a 50- foot diameter. No. 2. Julys, 1952 25 25 (broken stub) .3 April 23, 1953 42 17 + 26 June 23, 1953 56 22 + 36 No. 3. July 16, 1948 26H 37 Caught at the same place July 5, 1949 68 lOlJi on both occasions; in a little less than a year this female grew to small adult size. No. 4. August 23, 1950.. . 36 55 .9 The interval between May 19, 1951 46 691^ 1.7 captures included about two months of active life, plus the hibernation period; caught at the same place on both occasions. No. 5. September 2, 1950 34 J4 33 (broken stub) Tail broken at first cap- June 12, 1951 45 48 + 3 2.6 ture; recaptured 40 feet from original location. No. 6. July 28, 1949 36 56 Recaptured 75 feet from AprU21, 1950 49 83 2.5 original location. No. 7. August 31, 1951.. . 38 58 All three captures within May 25, 1952 48 82 a 70-(oot diameter. June 30, 1962 63 J^ 67+26 No. 8. August 23, 1950... 36 44 (broken stub) .7 Tail broken at first cap- July 23, 1951 69 37 + 49 ture. Capture sites 150 feet apart. No. 9. August 23. 1949.. . 39 53J^ (regenerated) This male was retarded June 7, 1950 46 70}4 (regenerated) 2.1 in growth, being still July 23, 1950 58 88 (regenerated) 3.7 well short of small September 3, 1950 62 91 (regenerated) 4.9 adult size as its second hibernation period ap- proached ; all four cap- tures recorded within a few yards. No. 10. July 31, 1949 38 23 (broken stub) Capture .=!ites June 17, 1950 58 43+36 3.6 20 feet apart. No. 11. August 13, 1949.. . 40 66 Approximately a year August 8, 1950 63 90 (regenerated) 5.6 after its original record this skink was recap- tured 80 feet away, still short of small iadult size. No.ia August 19, 1949.. . 42 40 (broken stub) All three captures within June 13, 1950 58J4 58+28 4.1 a 50-foot diameter. Julys, 1950 63 62+31 5.9 80 Un'i\'ersity of Kansas Publs., Mus. Nat. Hist. Many other young were not caught and marked until the growing season following their first hibernation, and were recaptured within this second growing season weeks or months after they were origi- nally marked, and after tliey had made substantial growth. Those recaptured near the end of this second growing season, when they were a year old, or a little more, usually had attained small adult size or were nearing it. Selected records of these yearUngs are presented below. Table 9. Selected Records of Individual Skinks Marked as Yearlings (After Emergence From the First Hibernation) ant> Recaptured One or More Times the Same Year. Rapid Growth Is Shown. Date Snout- vent length in mm. Tail length in mm. Weight in grams Remarks No. 1. Mav2, 1951 September 25, 1951 38 62 531^ 25-r31 Capture sites 30 feet apart. No. 2. May 8. 1951 .August 2, 1951.. . . 39 60 57 67+25 Capture site.i 150 feet apart. No. 3. ApriI17, 1952 June 23, 1952 39 57 55 73 (regenerated) 1.1 Canture sites 30 feet apart. No. 4. May 20, 1952 May 28, 19.52 June 9, 1952 45 47 53 67 71 82 Capture sites 15 feet apart. No. 5. May 22, 1952 July 20. 1952 48J^ 63 77H 106 2 5 3 Capture sites 10 feet apart. No. 6. June 11, 1950 September 2, 1950 49 63 49 (broken stub) 63^31 2.4 4.9 Capture sites 20 feet apart. No. 7. Ajiril 14, 19.'50 May 29, 1950 47 50 72 82>^ 1.9 2.5 Capture sites 50 feet apart. No. 8. May 12, 19.52 June 18, 1952 49 61H 77 98 Capture sites 60 feet apart. No. 9. June 4, 1950 August 1, 1950 54 64K 89 101 (broken stub) 2.8 5.7 Both captures at same site. No. 10. June 11, 1950 September 2, 1950 49 63 49 (broken stub) 63t31 2.4 4.9 Capture sites 20 feet apart. No. 11. June 13. 1949 Augusts, 1949 57 70 68 (regenerated) 37+11 Adult skinks can be found in greatest numbers in the breeding season and many of the young that were marked were recaptured as newly matured breeding adults soon after their second hiberna- tion, often still short of average adult size. Selected records of such individuals are presented below. Life History and Ecology of Five-lined Skink 81 Table 10. Records of Individual Skinks Mabked as Yoxjng and Recaptured as Adx^-ts. Date Snout- vent length in mm. Tail length in mm. Weight in grams Remarks No. 1. Male August 21, 1950.. . May 30, 1952 34 69 48 37+49 .7 Probably less than a month old at first cap- ture; at second capture 21 months later and 185 feet away, he had red facial sutiusion al- ready somewhat faded as the breeding season waned. No. 2. Male July 31, 1949 August 22, 1949.. . May 19, 1951 39 47 73 64 75 69 (regenerated) All three captures within a 70-foot diameter. No. 3. Male August 5. 1949. .. . May 3, 1951 36 67 57 103 "5.1 " Capture sites 10 feet apart. No. 4. Male June 16, 1951 May 28, 1952 44 63 41 (broken stub) 77 (regenerated) Capture sites 535 feet apart. No. 5. Male April 12, 1950 May 1, 1951 45 67 73 17+48 1.9 Capture sites 100 feet apart. No. 6. Male Api-U 12, 1950 August 10, 1950. . . May 12. 1951 46 67 71 4 + 15 75 (regenerated) 77 (regenerated) 1.3 5.3 This individual had at- tained approximately average adult size by the 1951 breeding sea- son; all three captures were within a distance of 90 feet. No. 7. Male April 30, 1950 June 15, 1950 May 19, 1951 48H 56 67 78J^ 94 90 (broken stub) 2.4 2.9 No. 8. Male May 3, 1950 May 29, 1951 47 75 51+4 115 (regenerated) 1.7 Ca)iture sites 450 feet apart. No. 9. Male June 2, 1949 May 2, 1950 51 66}^ 46 (broken stub) 31Ji+51 ■7'.0" Capture sites 90 feet apart. No. 10. Male May 20, 1950 June 21, 1950 August 21, 1950.. . 58 61 70 921^ 95 108 (broken stub) 4.0 4.7 7.2 Capture sites within 40 feet. No. 11. Male June 25, 1950 May 1, 1951 62 71 100 113 5.1 7.1 No. 12. Female Anril 15, 1950 May 20. 1951 46J^ 72 73H 113 1.5 Capture sites 160 feet apart. No. 13. Female June 11, 1950 May 25, 1951 51 66 69 40 2.5 Capture sites 20 feet apart. No. 14. Female June 6, 1949 May 20, 1950 June 9, 1950 52 68H 71 47 (regenerated) 69 (regenerated) 71 (regenerated) "i'.h" Capture sites 20 feet apart 6— S559 82 UNrvERSiTY OF Kansas Publs., Mus. Nat. Hist. Table 10. — Concluded Date Snout- vent length in mm. Tail length in mm. Weight in grams Remarks No. 15. Female July 2. 1950 60 100 4.2 Capture sites May 21, 1951 74 33n 35 20 feet apart. No. 16. Female .lune 12, 1950 57 83 3.1 Capture sites May J, 1951 71H 53 (broken stub) 6.4 35 feet apart. No. 17. Female This female probably June 22, 1949 62 24 (broken stub) hatched in July 1948 May 22, 1950 72 27 + 7 9.0 and was neanng adult size when first caught at an age of a little less th.Tn a year. By the next breeding season it was an average sized adult; both captures at same site. No. 18. Female This female probably was July 4, 1950 64 30-55 4.3 approximatelv a year May 23, 1951 73 31 + 62 old when first caught, and she grew to aver- age adult size by the next spring; both cap- tures at same site. No. 19. Female This female was about a July 5, 1950 61}^ 92^ f regenerated) 4.7 year old when first cap- June 14, 1951 73 1 11 (regenerated) 8.2 tured : loss of weight in June 29, 1951 74 106 (regenerated) 5.0 July 1951 was caused by its laying a clutch of eggs. All three cap- tures were within a 15- foot diameter. 70 60 E E ^50 I I- o 40-=. LJ _J H30 20 o 2 T _ 1 .1 -t L.. -1' J ; ,. . . ]i 1." _L ' '*'* 1 y> ] ■ I],'"" - -■ ;ft :'' -• - - f J; ..;'. -- - • a r ' ' 1 * - ,. • -. ■ ■ 1- .4i |Iha JCHIN G SIZELtf- — F-- — -|i — tH >z ^ h ^oIq: >: ^ >-, eiQ::Q:>: Lu a < ^ < 2 =0 1949 ZD \jjCL < =D < co< s =^ =3 < co< :e O -3 < r 3 UJQ- < UJ >, O 3 3 =i < 1950 1951 1952 Fig. 12. Sizes of immature skinks of successive annual broods, grouped in biweekly or monthly intervals, with mean, standard error, standard deviation, and extremes shown for each group. Life History and Ecology of Five-lined Skink 83 A certain small percentage fail to attain minimum adult size or breeding maturity by the time of emergence from their second hibernation. Among 77 individuals marked as young either soon after hatching or in spring and early summer, and recaptured the following spring, only one had failed to grow to adult size. It was 46.5 mm. in length when marked on June 13. When recaptured on April 25 of the following year, it had grown to a length of 59 mm.,, still short of minimum adult length. During the interval between captures it had maintained about the average growth rate. Its failure to attain maturity was obviously the result of its early retarda- tion, and probably late hatching was primarily responsible. Al- though this is the only individual with known history, which failed to attain breeding maturity after its second hibernation, occasional specimens are taken in spring which are somewhat below adult size but seem too large to be young hatched the preceding summer. Obviously, the incidence of such failure from year to year would be influenced by weather conditions, and an unusually cool summer may result in such delayed laying and hatching that an unusually large proportion of young might fail to attain sexual maturity at the usual time. At more northern localities, the percentage of such failures might be expected to increase. At the northern edge of the range attainment of breeding maturity may normally require more than two years. Such delayed development would result in a drastic reduction of the reproductive potential which might be critically limiting to the species, even in an otherwise favorable environment, as the population would be unable to replace rapidly enough the individuals eliminated by normal mortality factors. In contrast to the delayed development of those that have failed to attain maturity at an age of two years, is the accelerated develop- ment of those that have already more than doubled in length before the first hibernation, and continue to grow rapidly after emergence. By late spring they are already approaching adult size, perhaps even before laying has occurred, and while breeding is still in prog- ress. It is certain that in northeastern Kansas there is no breeding by such accelerated individuals approaching adult size at an age of nine or ten months. Farther south in the species' range with a much longer growing season, there is perhaps some possibiHty of such early breeding by first-year individuals. This would reduce by more than half the length of time required for a generation, and would tremendously increase the reproductive potential. With such added impetus to its reproduction the species might be able to withstand greatly increased predation pressure, or other mortality factors. 84 UNrvERSiTY OF Kansas Publs., Mus. Nat, Hist, Extremes of acceleration or retardation are relatively rare in the population studied. Nevertheless, in April there are some indi- viduals between 50 and 60 mm. in snout- vent lentrth which cannot E E X I- UJ O z 70 60 50 40 30 20 10 \ • ■■" -^\^\ • '' A- ^ ^ <^ f^ ■ ^ p • s^ ^fi' V ^ jr^ -* / ^ r^ • f • J ,• .• ^* lb / 1 / 1 k , / *' I' • >/ 'I 1 V u JULY AUG SEPT APR MAY JUNE JULY AUG. SEPT APR. Fig. 13, Growth curves of successive annual broods (designated by the year of hatching), superimposed to bring out differences in trends resulting from changes in weather from year to year, be classified with certainty as to their age group, and might be either accelerated individuals about nine months old or retarded indi- viduals about 21 months old. Life History and Ecology of Five-lined Skink 85 The spread in size for any given age group is especially large, if data from diflFerent years are combined. A typical individual, having a snout-vent length of 25 mm. at hatching in mid-July may have attained 30 mm. by early August, 35 mm. by late August, and 45 mm. by the time it hibernates late in September. Emerging shortly before the middle of April it may grow to 50 mm. by the end of May, 58 mm. by the end of June, and more than 60 mm. by the end of July when it is a little more than a year old. By the time of its second hibernation it may have attained a length of from 65 mm. to 70 mm., and emerges from this hibernation as a breed- ing adult. APRIL MAY JUNE JULY AUG. SEPT OCT APRIL MAY JUNE JULY AUG. SEPT Fig. 14. Records of growth of immature individual sldnks, both hatchlings and yearlings, that were marked in one year and recaptured the next. In reptiles in general there is a wide range in adult size, and the extent and rapidity of continued growth after attainment of sexual maturity and minimum adult size is still insuflBciently understood. Information bearing on this problem was obtained in the present study from the recapture of marked skinks already measured as adults. It is evident that the growth rate of the young, amounts to as much as 15 mm. per month in snout-vent length in the late sum- mer period from hatching until hibernation, averages perhaps three or four mm. per month in the summer after emergence from the first hibernation, and tapers oflF rapidly as adult size is approached. One hundred of the skinks marked as adults or subadults and re- captured after intervals of months, including, in most instances, one or more hibernation periods, represent in the aggregate, 87 years of 86 UxR'ERsrri' OF Kansas Publs., Mus. Nat. Hist. growth. These records show that after minimum adult size of 65 mm. is attained, growth slows abruptly, and that by the time a length of approximately 75 mm. is attained in most instances growth has become extremely slow in males and has virtually stopped in fe- males. Males attain a maximum size several millimeters larger than that of females. Individuals differ greatly in their growth, how- ever; some adults continue to grow rapidly till they near the maxi- mum size, whereas others apparently stop growing when they are still below average adult size. Unusually large specimens are not necessarily old, but may have attained their size only a year or two after reaching maturity through the accelerated growth resulting from abundant food and predisposing genetic factors. Likewise, unusually old individuals are not necessarily the largest, but may be only a little above average adult size. It may be assumed that no gro\\i:h occurs during the period of winter dormancy, which occu- pies approximately half the year in the population studied. To compute growth rates, in those recaptured after an intervening hibernation, periods of hibernation, arbitrarily estimated as six months, were subtracted from the time elapsed between captures. Table 11. Average GROwnrH Rate in a Selected Sample of Skinks OF Adult Size. Males Females Size Group Average growth mm. per month Number of skinks in sample Average growth mm. per month Number of skinks in sample 65-68 mm 69-72 mm 1.4 .7 .7 .4 11 12 13 7 .8 .4 .3 12 21 73-76 mm 21 77-80 mm Opportunity to compare the rapid growth of young during their first year of life with the relatively slow continued growth after at- tainment of sexual maturity is afforded by the records of skinks caught and marked while yet immature and recaptured in two or more successive years after their attainment of sexual maturity. The records of selected individuals of this group are presented be- low. With the exception of number three, all in this series are of the 1949 brood, and probably all hatched within a two-week period. Life History and Ecology of Five-lined Skink 87 Table 12. — Records of Indiyidual Skinks Marked as Yoxjng and Re- captured Repeatedly After Attainment of Adult Size, Showing Trend of Progressively Slowing Growth. Date Snout- vent length in mm. Tail length in mm. Weight in grams Remarks No. 1. No. 2. No. 3. No. 4. No. 5. No. 6. No. 7. Male April 12, 1950.. August 30, 1950 May 23, 1951.. April 28, 1952.. Male July 5, 1950. July 28, 1950 May 3, 1951 . June 21, 1951 May 1, 1952. Male June 22. 1949 May 4, 1950. June 17, 1950 May 15, 1951 May 13, 1952 April 6, 1953. Female July 13, 1949.. June 1, 1950. . . August 21, 1951 May 1, 1952. .. Female April 15, 1950 June 5, 1950 May 25, 1951 September 28, 1951 April 26, 1952 April 24, 1953 Female April 21, 1950 May 7, 1950 May 3, 1951 May 2, 1952 August 27, 1952.. . Female June 5, 1950. . . July 13, 1950. . July 29, 1950. . August 21, 1951 May 28, 1952.. 43 56 68 73 61 64 68 72 78 65 72>^ 73 80 82 82 27 54H 74 76 43 52J^ 71 73 74 76 46 48 74 78 79H 51 59 64 69 73 71 56+21 59+32 62 + 38 92 J^ (regenerated) 97 (regenerated) 96 (broken stub) 101 >^ (regenerated) 101 (regenerated) 111 115 116 125 125 104 (regenerated) 34 J^ 93H 119 123 70 87 82 + 29 111 (regenerated) 113 (regenerated) 114 (regenerated^ 75 15 (broken stub) 29+57 25+64 95 (regenerated) 82 93 98 80 (broken stub) 83+93^ 1.5 5.4 6.6 5.2 5.4 5.8 7.3 7.8 3.1 10.0 1.4 2.8 7.4 2.1 2.0 8.5 8.3 2.5 3.9 4.4 5.0 At an age of 33 months this male was far short of maximum size, and smaller than some males a year younger; all four captures with- in a 65-foot diameter. At an age of approxi- mately one year this male was approaching small adult size; when last captured at an age of 34 months, he was a large adult. All five records within a 190- foot diameter. This skink was nearly a year old and nearing adult size when first captured; recaptured in each of the four succeeding years, he showed slowing growth. He was near the maximum size at the time of hia last capture when he was about 57 months old, and evidently had stopped growing (for movement see No. 2, p. 110). This individual, marked when less than two weeks old, had grown to nearly the maximum female size at an age of 34 months; all four captures within a 175- foot diameter. (See Figure 24). All six records within a 65-foot diameter (See Figure 21). Hatched in July 1949, this skink had attained the maximum female size at an age of a little more than three years; (for movement see Figure 25). Hatched in July 3949, this skink was 11 months old and about half -grown when it was marked. When last caught at an age of 35 months it was of aver- age adult female size, having grown less than numbers 4 and 6 at the same age. All five cap- tures were within a 60- foot diameter (Fig. 24). 88 UNn-ERsrrY of Kansas Publs., Mus. Nat. Hist. Table 12. — Concluded Date Snout- vent length in mm. Tail length in mm. Weight in grams Remarks No. 8. Female Hatched in July 1949. April 26, 1950 May 24, 1951 50H 78J^ 107 (regenerated) 2.7 this skink was of aver- 74 age adult female size April 28, 1952 78 93 (regenerated) 8.5 and was breeding in AprU23, 1953 80 93 (regenerated) May 1951; it grew nearly to maximum fe- male size in the next 11 months. .All captures within a 70-foot diame- ter. No. 9. Female July 5, 1950 60 95 4.5 All three captures at the August 6, 1951.. . . 71 106^ 5.6 same site. May 28, 1952 72 110 8.5 No. 10. Male Hatched in July 1949, April 23, 1950 46^ 66 (regenerated) 1.8 this male grew less June 13, 1950 52 1^ 26+3 2.7 rapidly than most, and September 2, 1950 66 32 + 51 6.2 in the spring of 1953 May 29, 1951 67 33 + 58 was smaller than some August 3, 1951 70 94 (regenerated) others that were a year March 27, 1953. . . 74 78 (regenerated) 7.i younger, or even two years younger. Nell. Female April 26, 1950 U ay 24, 1951 50H 78M 2.7 This skink had attained 74 87 maximum female size April 28, 1952 78 72 + 21 8.5 when she was a little April 23, 1953 80 73 f 20 less than four years old. DifFerences in their growth rates therefore reflect diflFerences in sex, individual vigor, and local situation, in individuals living at the same time and within the same general environment. Changing weather, and other factors that vary from year to year cause marked diflFerences in the dates of important events in the annual cycle, and in the stage of development at any given date. Data are available for five successive annual broods of young, those of 1948, 1949, 1950, 1951, and 1952, and each brood diflFers from the others to some extent, as shown in Figures 11 to 13. In 1949, for instance, young hatched relatively early, and probably most of them were active by the middle of July. They made rapid growth in August, averaging larger than young hatched in other years on any given date in late summer. However, they retired into dormancy early in the fall. Cool and dry weather in early September ended their activity for the season. In 1950, young hatched, on the aver- age, at least three weeks later, about the first of August, but they remained active until late in September, and by hibernation time had partly caught up to the stage of development attained by the young of 1949. Most young of 1951 hatched late in the first half of Life History and Ecology of Five-lined Skink 89 August, and at first were smaller than those of 1950 and much smaller than those of 1949 on corresponding dates, but favorable weather in the early fall hastened their development. By early Sep- tember they had caught up and passed the stage of development of young of 1950 and by the time they retired to dormancy in late Sep- tember, they had reduced by half the size-advantage of the young of 1949 at the time these latter retired into hibernation. The young of 1951 appeared to be few in numbers, and a lack of competition may have been a factor in their rapid early development. APRIL MAY JUNE JULY AUG. SEPT OCT APRIL MAY JUNE JULY AUG. SEPT Fig. 15. Records of growth in another group of recaptured young that grew less rapidly than those of Fig. 14. The young of 1948, first sampled after their emergence from their first hibernation in mid-April of 1949, were then somewhat inter- mediate in size as compared with those of 1949 and 1950 at the same times of year. Their subsequent development was rapid; by late May they had caught up and passed the stage reached by the 1949 young at the same time of year. The young of 1950 after having a late start, were further set back by cold weather in April 1951 de- laying their emergence from hibernation. As a result they were still unusually small in late April and May. Even though they grew rapidly subsequently, they were consistently smaller than those of other broods on corresponding dates. Favorable fall weather pro- longing the 1951 growing season into late September beyond the time of retirement in other years may have permitted many of them to attain adult size. 90 University of Kansas Publs., Mus. Nat. Hist. E e X I- o UJ > I O z APR. MAY JUNE JULY AUG. SEPT OCT. Fig. 16. Records of immature individual skinks marked and recaptured within the same growing season, showing the trend of rapid growth, and dif- ferences in growth rate between individuals. The varying fortunes of the several annual broods studied were closely correlated with weather trends, and suggest possible effects of slight changes in climate. An unfavorable sequence of weather might bring about drastic reduction of the population without caus- ing any direct mortality. A late spring in two successive years would have cumulative effect in delaying emergence and breeding of adults the first year, and delaying in the second year emergence of the young, already retarded by the lateness of their hatching. If this sequence were followed by onset of unusually cool and dry weather in early September, or even in late August, the young might Life History and Ecology of Five-lined Skink 91 be "caught short," and forced to hibernate while still in the 50-60 mm. size class. Emerging the following spring, they might have failed to mature sexually, reducing by perhaps half the number of productive adults. At the northern extreme of the species' range, length of growing season may be more critical than extremes of tem- perature in limiting the numbers and distribution. Growing seasons that average long enough and warm enough to permit attainment of maturity by onset of the second hibernation period may be essential to the species. While no two annual broods of young in the same locality come under exactly the same weather influences, extremes of retardation or acceleration continuing throughout development are relatively rare. Retarding efiFects of unfavorable weather caus- ing delayed breeding and hatching, may be ofiFset by prolongation of warm weather in the fall thus delaying hibernation, or by warm spring weather hastening emergence from hibernation. Under favorable conditions an adult female produces about ten offspring annually of which about half are females. It is calculated that if all survived, after ten breeding seasons, the progeny of an original female might have increased to a population of more than 97,000, under the climatic conditions of eastern Kansas, permitting attainment of breeding maturity late in the second year of life. In the same ten year period under climatic conditions delaying maturity until late in the third year of life (as seems normally to occur in E. septentrionalis and E. skiltonianus, and probably in E. fasciatus at the northern edge of its range) the original female would have produced a population of somewhat less than 7,800 assuming that all survived. With a long growing season such as occurs in the southern part of the range, it seems theoretically possible (though not probable ) that individuals might mature before the end of their first year, in time to participate in the next breeding season. If this should occur the original female might produce a population of more than 120 milHon by the end of the tenth breeding season. Changes in Pattern Progressive alteration of the color pattern is more rapid in males than in females and is synchronized with growth. During the first year of life changes in the pattern are gradual, and consist chiefly of loss in vividness. The blue of the tail is slightly dulled. The Hght lines become suffused with brown and the dorsolateral dark areas become paler, with light brown areas appearing on the corners of the scales and gradually spreading to replace the original black. In skinks that are in the second year of Hfe the striped pattern although 92 UNrvERSiTi' OF Kansas Publs., Mus. Nat. Hist. still conspicuous is made up of two shades of brown instead of the earlier black and white markings. Even in hatchlings, the dorsal part of the rostrum and the inter- nasals are of a somewhat neutral brownish color, matching neither E E X o UJ UJ > o to APR. MAY JUNE JULY AUG. SEPT OCT Fig. 17. Records of another group of immature skinks marked and recaptured within the same growing season. the light lines nor the dark interspaces of the striped body pattern. With advancing age this neutral brown color gradually spreads pos- teriorly on the head so that the striking lyrate marking of the bi- furcated dorsal stripe on the head in the juvenile become obscured by the time the skink has grown to small adult size, at 21 months. The top of the head is then dull brown, with a slightly mottled appearance caused by the different intensity of pigmentation in different areas. The stripes though still discernible, are faint and Life History and Ecology of Five-lined Skink 93 inconspicuous. Dorsally, on the body, the stripes are still con- spicuous, but are dull and lacking in contrast. At this stage, the dark lateral area is retained with intensity of pigmentation scarcely diminished. Table 13. Normal Range of Variation in Dorsal Striping of Head and Body, and in Color of Tail According to Age and Sex. Age, Size and Sex Condition of stripes Color of tail Sharp Distinct DuU Faint Absent Original Regenerated Small young body X X X X X X X X X X X X X X X X X X X X X X X X X X X bright blue bright blue dull blue mostly dull blue mostly brown and gray with scattered blue scales mostly brown ; occasional bluish scales brown; occasional bluish scales brown bright blue head Larger young body duller blue head Young adult female body gray-blue head Young adult male body gray-blue bead 3 year adult female body mostly head gray brown 3 year adult male body head Old adult female body brown head Old adult male body brown head 1 In tracing the gradual ontogenetic changes in the striped pattern, from the vividly contrasting colors of hatchlings to the dull, pattern- less coloration of old adult males, five descriptive terms have been applied to the successive stages: "sharp," "distinct," "dull," "faint," and "absent." To most individuals below minimum adult size, the term "sharp" is appHcable, although there is some loss in vividness in the larger young, as compared with hatchhngs. Fading of the original striped pattern proceeds more rapidly on the head than on the body. Upon emergence from their second hibernation at an age of about 21 months, the skinks, mostly grown to adult size, and ready to mature sexually, still show but little sexual diflFerence. They retain the hatchhng pattern essentially unchanged, but with colors dulled and contrasts reduced. Within a few weeks the newly ma- tured males undergo relatively rapid color change as the breeding 94 Unrtersity of Kansas Publs., Mus. Nat. Hist. season progresses. The stripes tend to fade and blend into the dark areas adjacent to them. In the two-year-old males stripes are dis- tinct to dull on the body and faint or absent on the head, while in females of the same age group, body stripes are sharp or distinct. Table 13 refers to adult pattern and coloration as they appear in the breeding season. After the breeding season, in late spring and early summer, when the red suffusion of the head and neck has faded in adult males, the original striped pattern, after having been almost completely suppressed may again become discernible. In- dividuals of the same size differ in extent of pattern change, and the color descriptions made of individuals were not sufficiently de- tailed to show fully the changes occurring between successive dates of capture. However, most large adult males taken later than mid- June had at least some trace of the striped body pattern and many of them had become so much like females in appearance that close scrutiny was necessary to determine their sex. They were especially like females in having the dark lateral area extending forward onto the cheek and setting it off sharply from the paler temporal region above it. In breeding males the head has no such dark markings and is suffused with red. Growth and Regeneration of the Tail Even among those skinks which have never broken their tails there is a wide range of variation in relative length of tail. This is partly a matter of relative growth since the proportions change during the course of development. Also there may be slight sexual difference and there is much individual variation. In fetuses still well below hatching size, the tail length is less than the snout-vent length. For instance, an egg in a natural nest 12 days short of hatching contained a fetus that had a snout-vent length of 14 mm. and tail length of 12 mm. (Figure 18). In the late stages of fetal development the tail growth is relatively rapid. At hatching, the tail is considerably more than half the total length. In a large series of young with snout-vent lengths from 30 mm. down to hatch- ing size of 25 mm. or less, the tail length averaged 130.8 per cent of snout-vent length. In larger young, up to a snout-vent length of 40 mm. or more, the tail continues to lengthen more rapidly than the body. In skinks that are about two thirds grown, the tails average relatively longer than in either larger or smaller individuals. In the sample representing the size class 50-54 mm. snout-vent length, the tails average 163.3 per cent of the snout-vent lengths, whereas in groups of adults of various sizes and both sexes, the tail length Life History and Ecology of Five-lined Skink 95 is near 155 or 156 per cent of the snout-vent length. Sexual di- morphism in tail length is slight if it exists at all; in adult males, tails averaged a little longer than in adult females. When a skink's tail is broken, there is almost no loss of blood. The fractured surface is rough and irregular, with exposed muscle masses protruding on the detached end and corresponding concavi- 180 170 - I o 160 - > 150 - I I- O ^I40t- z UJ o ct llJ Q. ID ■a X S 110 130 - 120- 100 90 - 1 1 1 1 1 1 i 1 i a- cT - " 5 \ -- ^ - , - -,, - ' ~ ~ - . __-' - _ ~ *■ ^_ _--.. _| t_ J c:!"'- -,^» 1 _ '~ y ~ / / / / 1 f / / / t t / i 1 t / / / / / / / / / t / / / •'FETUS 1 1 1 1 111! 1 1 1 1 1 11-15 16-20 21-25 26-30 31-35 36-40 41-45 46-50 51-55 56-60 61-65 66-70 SNOUT-VENT LENGTH IN mm 71-75 76-80 Fig. 18. Diagram showing relative tail-length ( as a percentage of snout-vent length) in skinks of different size groups that retain their original tails un- broken; in the early stages of growth the tail becomes relatively longer as size increases, but the trend is reversed before adult size is attained. For each series the mean, standard error, standard deviation, and extremes are shown. ties on the end of the stump tail retained by the lizard. The concavi- ties are soon filled with oozing blood, and a thick scab forms. As healing begins, the broken end presents a flat, slightly irregular sur- face. When the scab is sloughed off, a slightly convex surface of delicate, pale-colored new skin of the regenerating tail, is exposed. At first, no scale structure is discernible. As growth proceeds, the new tail takes on a bluntly conical shape. During the early stages of growth, it is well set o£f from the original portion by the abrupt 96 Untv'ersity of Kansas Publs., Mus. Nat. Hist. taper at the point of contact and by its paler coloration and dif- ferent texture, with no scales discernible at first, and later with fine and granular scalation. The new tail elongates until the more abrupt taper beyond the point of the break is no longer noticeable, and the coloration, surface texture and scalation match that of the original portion so closely that it is difficult to determine where the break occurred or even to ascertain that there has been one. On the regenerated tail, however, the scales are less uniform in size and less regular in shape. The regenerated tail, being different from lO li- -z. O LlJ s| fc o o ^ a. ^ LjJ < ^ : • . • •• • • .• • •• • . . • • •'•'. . :'■ . " * • .. '••:•... • • • ••/ .••..:• • • ^ • • • • • . * ...•.••. . • • •• • ••^.. ' '' • •• . .*•••■'.•■'• • • . ' . . . • . . " * . • • • . • •. • • • ■ •' . ■ . • • : • • ' • • • • t 1 '. I J I I I I I 1 < * . ' ' ' » 100 90 80 70 60 50 40 30 20 ' 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 ORIGINAL PORTION OF TAIL AS PERCENTAGE OF SNOUT-VENT LENGTH Fig. 19. Relative lengths of original and regenerated portions of tails in skinks which have had their tails broken and regenerated; for each individual, length of each part of the tail is expressed as a percentage of the snout-vent length. the original in internal structure, with a cartilaginous rod replacing the vertebral column, is less fragile and subsequent fractures are most likely to be on tlie part proximal to the regeneration. Never- theless, fractures of regenerated tails occur occasionally. In old skinks especially, the tail eventually may consist of three or more dis- tinct segments including the basal remnant of the original tail and the successive regenerations. When a break in the regenerated tail occurs, the detached portion is relatively inert, and is capable of only feeble twitching movements in contrast with the lively wriggling normally displayed in a newly detached tail that includes part of the central nervous system. Rate of growth in the regenerating tail is controlled by a variety of factors, such as age, condition, and activity of the individual, and Life History and Ecology of Five-lined Skink 97 site of the fracture. A break occurring early in the skink's Hfetime results in regeneration more complete than occurs in an adult sus- taining the same type of injury. The regenerated tail eventually may be longer and thicker than the lost part if the lizard is young and still growing. But the regenerated tail is never so long as the original one would have been. Regeneration is most extensive in those tails broken near the base. The farther from the base the break occurs the shorter is the part regenerated. As a result, tails that have had time to regenerate do not differ greatly in total length Fig. 20. Diagrams showing typical extent of tail regeneration in skinks having tails broken at different points, X approximately %. Original parts of the tails are at the right. regardless of where the break occurred. However, the nearer the break is to the base, the shorter is the total tail-length after regen- eration (Figures 19 and 20). If only the tip of the tail is lost, re- generation may not occur. In the skinks examined that had regen- erated tails the proportions varied over a wide range. Presumably, in many, growth of the regenerated portion was still incomplete. 7—3559 98 University of Kansas Publs., Mus. Nat. Hist. Under favorable conditions regeneration occurs at a relatively rapid rate. After a period of healing the new tail grows with a sudden spurt, making most of its gain in length within a few weeks. Then growth abruptly slows or ceases altogether. In young sim- ilarly rapid growth of the regenerating tail occurs, but subsequently Table 14. Records of Regeneration of the Tail in Indfvidual Skinks Marked and Recaptured. Age and Sex Date Snout- vent length in mm. Tail length in mm. No. 1. Adult male June 1, 1951 June 26, 1951 August 17, 1951.. . April 29, 1952 73 73 76 76 38 (newly broken) 38 + 14 40+45 40+45 No. 2. Immature May 28, 1949 October 15, 1949. . 51 69 46 (newly broken) 51+21 No. 3. Immature June 11, 1950 September 2, 1950 49 63 49 (newly broken) 63+31 No. 4. Immature female August 10, 1950... June 14, 1951 62^ 68 60 (newly broken) 62+17 No. 5. Adult male August 14, 1950.. . September 3, 1950 April 27, 1951 67M 681^ 69 77+4H 77+6H 78+9 No. 6. Adult male April 7, 1950 July 27, 1950 67 71 38 (newly broken; separated end 66) 39+47)^ No. 7. Adult male May 28, 1951 June 14, 1951 September 22, 1951 70 71 76 18 (newly broken; separated end 100) 18 + 1 19+29+7M No. 8. Adult male June 12, 1951 July 28, 1951 72 76 33 (recently broken) 36+31 No. 9. Juvenile May 2, 1951 May 14, 1951 May 19, 1951 45 45 45 47 + 1 47+3 47+5 No. 10. Subadult female. . June 7, 1952 June 24, 1952 64 64 51 (recently broken) 51 + 11 No. 11. Juvenile August 19, 1949... June 13, 1950 August 5, 1950. . . . 42 581^ 63 40 (newly broken) 58+28 62+31 No. 12. Adult male May 17, 1951 June 12, 1951 78 78 20 (newly broken) 20 + 13 Life History and Ecology of Five-lined Skink 99 the increase is more gradual corresponding to the over-all growth of the lizard. In numerous adult skinks marked, and recorded as having well-regenerated tails, the proportions recorded at subse- quent captures months or years later were still just the same, dem- onstrating that extent of regeneration is not proportional to elapsed time. Those adult skinks having unusually long regenerated tails presumably are individuals in which the original tail was lost early in life, and the potentiality for regeneration is probably somewhat less in older individuals, especially those that have stopped growing. Successive records of selected individuals are listed in Table 14 to illustrate trends in regeneration of the tail. In those instances in which the tail is referred to as "newly broken" the separation usually occurred as an accident at the time the lizard was captured, while in those designated as "recently broken" separation had already occurred in some earlier accident but regeneration was not yet perceptibly underway. In the "Tail length" column, plus signs separate the original portion of tail, on the left, from the regener- ated portion, on the right. As in many other kinds of lizards, the tail in the five-lined skink serves as a reservoir for fat, which may be drawn upon for nutri- tion in time of food scarcity. An individual that is in good condi- tion has a plump and rounded tail. Fat comprises much of its bulk. Upon emergence from hibernation this fat supply is not noticeably depleted. Brooding females in the latter part of the incubation period have the supply of caudal fat most noticeably depleted, and their tails may appear emaciated, with kinks on the terminal portion. It is my impression that in adults the capacity for storage of fat is most developed in the females, and that their tails vary in proportions more than do those of males. The capacity to shed the tail easily seems somewhat inconsistent with this func- tion of fat storage. Loss of the tail sometimes involves loss of a large amount of reserve fat. Many detached tails that were broken accidentally at the time of the skinks' captures were weighed. In those that were broken oflF near the base and were not previously regenerated, weights were usually 16 to 20 percent of the lizards' total weights. Movements Data obtained concerning the movements of these skinks demon- strated that individuals tend to limit their activities to small areas thoroughly familiar to them, and wander but little. Although the nature and extent of movements in reptiles in general, and in lizards especially, are poorly known, my findings are perhaps what might 100 UNrv'ERSiTY OF Kansas Publs., Mus. Nat. Hist. be expected from the studies of earlier workers on various other species of reptiles. Goin and Goin (1951:29) observed that Eumeces laticeps in Florida lives in hollow stumps, each individual excluding other adults from its stump but tolerating young. Movements have not been studied in detail in any member of the Scincidae, however. The observations of Goin and Goin, and those of other authors, seem to indicate that E. laticeps is territorial, and that each indi- vidual centers its activities about a tree or snag, regularly using the same hollow as a shelter and home base. In contrast, E. fasciatus is not territorial and has no regular home base. The iguanid genus Sceloporiis is perhaps better known than any other kind of lizard as regards its movements. Studies by Newman and Patterson (1909), Stebbins and Robinson (1946), and Fitch (1940) on three different species have shown that individuals of Sceloporiis keep to small individual areas, and that territoriality is well developed, in some species at least. Among other reptiles, turtles are much better known, as detailed studies of movements have been made on several species, of which the life histories and ecology have been thoroughly investigated ( Nichols, 1939; Cagle, 1942 and 1944; Woodbury and Hardy, 1948; Stickel, 1950). They have been found to have well-defined and fairly extensive home ranges, which are not defended as territories. Studies of movements in several different kinds of snakes, by Blanchard and Finster (1933), Stickel and Cope (1947), Fitch (1949), Lowe and Norris (1950), and Carpenter (1952) have shown that these reptiles usually have definite home ranges, which may be several or many acres in extent. Their home ranges are not defended as territories against other members of the species. In general, turtles and snakes have been found to occupy home ranges that are much larger than those of lizards. Most information concerning movements of Eumeces fasciatus has been obtained from the recapture of marked individuals. Actual distances of travel, and the time, frequency and motivation of move- ment was uncertain. A skink marked, recorded, and subsequently recaptured at a second location may have wandered widely in the meantime, visiting points relatively remote from either location of capture. The two points of capture may be within a home range regularly or occasionally covered by the individual in the course of its routine activities; or the second point may have been recorded only after a permanent shift of activities away from the area within Life History and Ecology of Five-lined Skink 101 which the original point was located. Various types of movements probably were involved. Interpretation of the records is difficult because of the paucity of direct observations on the behavior and movements of skinks under natural conditions. Often when one is alarmed, it will run as much as 30 feet, in a fairly direct course, to a tree or bush or rock where it can find refuge. Undisturbed individuals move about slowly and circuitously. It is difficult to keep one under observation for any length of time because of the secretive habits causing it to keep under cover, as much as possible while moving about, and to hide in response to any slight disturbance. It is obvious that individuals shift their activities from time to time, occupying new areas either abruptly or by gradual stages. Even though a successful skink has a life span of several or many years, the populations on the small study areas were found to be much altered from one year to the next. Presumably this change was brought about largely by shifts in home ranges. Several shifts of hundreds of feet were recorded, but the chances of recovering marked individuals that moved so far were relatively poor because their movements generally took them beyond the limits of the study area to locations where recapture was unlikely. Skinks often were caught at their hiding places beneath rocks or other sheltering objects. In many of these instances it was evident from the posi- tion, temperature and state of activity of the lizard that it had been in the open but had become alarmed as the collector drew near and had retreated unnoticed to its shelter just before capture, whereas in other instances it was obviously at rest in its chosen shelter. Ex- cept for females in their nest burrows individuals were not ordinarily recaptured regularly at the same hiding places. They may seek new hiding places after each period of activity. However many of the skinks captured were taken again, after long intervals, near the same places. Time elapsed between suc- cessive captures for diflFerent individuals ranged from one day to 47 months. Of the total of 323 recaptured by September, 1952, approximately half, 162, were taken after intervals including one or more hibernation periods. In appraising home ranges and detecting the occasional shifts over a relatively long time span, chronology of the records needs to be taken into account. Records clustering about the same center seem to indicate continued occupancy of an estabHshed home range. However, when one or more early records are well separated from one or more later records, a shift in range 102 Uxn^Rsrri' of Kansas Publs., Mus. Nat. Hist. seems probable. In some instances successive records were pro- gressively farther from the starting point suggesting two or more shifts in the same direction from an original home range. Although recorded movements varied from a few inches to hun- dreds of yards, the most noteworthy feature in general was the short distance between points of capture (considered in relation to the potential mobility of the lizards) after days, weeks, months or years. In many instances no movement was demonstrable, even though successive points of capture were not exactly the same. Named natural landmarks, mostly trees, boulders and logs, well distributed over the study area, were used as a basis for locating points on the map. Direction and distance in feet to the nearest landmark was recorded for each site of capture, but for distances of more than 25 feet estimates were made to the nearest ten feet. Usually at least one landmark was available within a 50-foot radius from any point where a capture was made. Occasional estimates made for distances of more than 50 feet, or even more than 100 feet, in the absence of suitable landmarks nearby, were sources of inaccuracy. For such estimates errors of up to ten feet were common, and some errors of greater magnitude were made. For most individuals successive sites of capture tended to cluster within a small area, but the occasional outlying capture sites indi- cate that each individual does range outside the area in which its activities are concentrated. These occasional excursions cannot be consistently attributed to any one ecologic requirement, nor are they limited to any particular time within the season of activity. Adult males, however, tend to make longer movements in the brief period of concentrated sexual activity, thereby increasing their chances of finding mates. Similarly, adult females may wander beyond their usual ranges in search of suitable nesting sites. The home range may be thought of as consisting of a small central por- tion where activities are largely concentrated, and an outer area several times as large, familiar to the animal but used to a lesser extent by it. The activities gradually become more diflFuse farther from the central part of the home range. In the five-lined skink, home ranges are unlikely to approximate the circular shape because they are molded with respect to environmental features that are not uniformly distributed. A rotting log, an old tree with decayed hollow base and nearby fallen slabs of bark and dead limbs, a rock outcrop with numerous deep holes and crevices, or a group of flat rocks in a forest glade fulfill requirements not met in the surround- ing habitat with the result that home ranges are built around them. Life History and Ecology of Five-lined Skink 103 Consequently a home range may be long and narrow, with maxi- mum diameter several times the minimum diameter. The usual concept of home range, as a finite area with well de- fined boundaries is not entirely satisfactory for an animal with the habits of the five-lined skink. The skink spends much of its time in inactivity underground or otherwise concealed and sheltered, and when it does move about it takes advantage of natural travel- ways over rock surfaces, tree trunks, and logs. If a log happens to be the home range center, the skink may travel the length of the log many times without making a comparable trip at right angles to this axis of travel, although it may make short side dashes to secure food. On more extended forays, the directional sequence of move- ments is largely controlled by the distribution of suitable cover and travel routes, as the skink avoids both open areas and dense vege- tation. Outlying portions of the home range probably are not uniformly covered but are reached only occasionally as the lizard is led along some natural travel route, or after it has visited, in suc- cession, a series of locations attractive in providing shelter or food. Marked skinks were recaptured at distances up to 680 feet from points of original capture. Considering only the most remote points of capture for those individuals recaptured more than once, the average recorded movement for the entire group of 323 recaptured skinks was 58 feet. This figure provides a basis for comparing vagil- ity of this species with others. Eliminating some individuals of in- definite status, the average movement for 75 adult males was 69 feet; for 102 adult females, 45 feet; and for 112 young, 61 feet. For the adult females, home range data are biased by the fact that many were caught repeatedly at or near their nests. It is not clear whether females that do not have nests range less widely than males. Only 15 individuals, less than five per cent, had moved more than 250 feet. These longest movements were: 680 feet, adult female, 26 months; 680 feet, adult female, 10 months; 680 feet, subadult male, one year; 650 feet, young to adult male, 22 months; 640 feet, subadult to adult female, two years; 535 feet, young male, 11 months; 510 feet, adult male, 11 months; 490 feet, young (sex un- determined), 10 months; 450 feet, young male, 13 months; 350 feet, young (sex undetermined), 10/2 months; 335 feet, adult female 13^2 months; 275 feet, adult male, 35 months; 275 feet, adult male, 24 months; 270 feet, young to adult male, 12^2 months. For those skinks caught on only two occasions, at diflFerent places, the single movement record provides some clue as to the location and size of the home range. No evidence was obtained to indicate 104 University of Kansas Publs., Mus. Nat. Hist. that the activities of these lizards center at fixed home bases. It may be assumed that any two successive captures of the same individual separated by a substantial time interval, will be distributed at ran- dom to each other within the area to which the animal's activities are confined. The varied techniques of capture, by hand and with diflPerent types of traps, would help to secure random distribution of capture sites. If the home range were covered uniformly by the animal in the course of its activities, any two random capture sites would be on the average separated by a distance equal to half the home range diameter. If the animal tends to concentrate its activities in the central part of the home range, as seems to be the case, the capture sites will be correspondingly closer together. For the 196 skinks that were caught on only two occasions, average movement was 62 feet. Within this group the 42 adult males that were recaptured only once had averaged movements of 58 feet. One had made an exceptionally long movement of 510 feet, which obviously was not entirely within its home range. Excluding this one long movement, the remaining 41 had moved on the average, approximately 47 feet (Table 15). Among the other skinks caught only twice one of 61 females and 8 of 93 young had likewise made such long shifts that it seemed inadvisable to include them in com- puting the size of the home range. Distance between points of capture showed little correlation with elapsed time. For 24 of the adult males that were recaptured in the same year they were originally marked, the average distance was 49 feet, whereas in the 17 others recaptured after one or more hiberna- tions the average movement was 45 feet. For adult females, the corresponding figures were, respectively, 22 feet and 29 feet; and for young, 33 feet and 66 feet. For those individuals recaptured twice, at different locations, the three points of capture show to a greater or lesser degree the posi- tion, and, in part, the extent of the home range. Of course, all three points may be concentrated near the center of the home range, or they all may be scattered along its edges. In general, however, each point will lie somewhere between the center and edge of the home range, separated from each of the other two points by a dis- tance of, on the average, approximately a home range radius. Table 15 shows that adult males and young tend to range more widely than adult females, and that young tend to shift to new areas more frequently than do adults. Many of the recorded movements (in addition to the long ones that were excluded from the home Life History and Ecology of Five-lined Skink 105 range computations) may have involved short shifts in ranges. If all such shifts could be definitely identified and eliminated from the computations, actual home ranges might be considerably smaller than those indicated by the present set of data. Home ranges approximately 90 feet across for adult males and young, and a little more than 30 feet across for females are indicated. Actual area of a home range would amount to only a fraction of an acre — from about one-seventh to less than one-fiftieth. The dash of an alarmed Table 15. Distances Between Successive Sites of Capture for Marked Five-lined Skinks on Stitdy Areas, Indicating Home Range Sizes. Age, Sex and Number of Captures Adult males Individuals captured just twice Individuals captured just three times.. . Individuals captured four or more times Adult females Individuals captured just twice Individuals captured just three times. . . Individuals captured four or more time's Young Individuals captured just twice Individuals captured just three times. . . Individuals captured four or more times Average maximum distance in feet between points of capture, and extremes 47 (225-0) 47 (130-0) 91 (200-0) 16 (90-0) 25 (90-0) 28 (90-0) 45 (160-0) 46 (150-0) 82 (175-0) Number of skinks included in sample 41 18 17 56 25 15 85 14 14 Number of skinks discarded from sample because of relatively long movements, indicative of shifts of range 1 2 4 3 1 8 2 skink to a place of refuge, though involving at most only a few seconds, may traverse a large part of its home range. Through long association the hzard is thoroughly famihar with the terrain, so that it can take full advantage of the pecuHar features in escap- ing, hunting, travehng or resting. Relatively few marked individuals were caught four or more times at different sites. For these individuals hsted below the distribu- tion of the sites is more or less indicative of shape and size of the home range in some instances. For some of them successive loca- tions of capture are shown and possible home ranges are outHned in Figures 21-25. 106 University of Kansas Publs., Mus. Nat. Hist. o .V ■5-50* 4-i5-:50.*4-24-53 \ \%> ooo ^ ,•* \ ;V ?\ :*: \^ 7-1 3-49*;/ -7-l3-50ifc^"-^JlI-^J Fig. 24. Sites of successive captures of marked skinks, a male and two females, in the Sldnk Woods study-area. No. 12: Four captures in 11 months, all within a 50-foot diameter, in 1951, on June 1 and 26, and August 27, and in 1952, on April 29. No. 13: Four captures in 15 days, all in July 1949 within a 10-foot diameter. No. 14: Four captures in 22 months, July 22, 1950 (as subadult), in 1951, on May 8 and Jime 5, and on May 13, 1952. Second location 295 feet south- no Unr'ersity of Kansas Publs., Mus. Nat. Hist. west of first, third 30 feet north of second, and fourth 650 feet east of second and third. Probably two shifts of range were involved. Adult Females No. 1: Six captures in 26 months; in 1950 at the same place on June 4 and 13, in 1951 on May 26 it had moved from the original quarry ledge loca- tion 680 feet south southeast down the slope to the pond rock pile, where re- captured on June 9, and in 1952 on May 21 and July 22. No. 2: Six captures at four locations all within a 25-foot diameter, in 13 months; June 5, 1950, and May 25, June 18, 26 and 29, 1952. On each occa- sion this female was hiding in a nest burrow, but she shifted to new nest sites as a result of disturbance by the investigator or flooding when there were un- usually heavy rains. (\\c^^4.23_50 5-7-5l»-;:5.4.50 *\\ °i ! ;•: ^ i4-24-5l ,''•5-2-52 ^\:. '^v \ \ 5-3-51 5-7-56W4-2I-50 / — ^ / {:• 8-27-52 J' y Fig. 25. Sites of successive captures of a marked male and a marked female, each taken in three different years in the Sldnk Woods study- area. No. 3: Five captures in 34 months, all within a radius of a few yards, at the pond rock pile, on August 8, 1949, June 5 and July 23, 1951, and May 15 and June 4, 1952. No. 4: Four captures in 34 months, all within a radius of a few yards at the pond rock pile, on August 8, 1949, June 7, 1950, May 30, 1951 and May 21, Life History and Ecology of Five-lined Skink 111 1952. It is notable that this female was taken only once in each of four dif- ferent years, her occupancy of this rock pile seemingly continuing throughout the duration of the study. No. 5: Four captures in two months, in 1950 on April 15, and on April 26 had moved 50 feet south; on May 23 she was approximately 50 feet from both second and third locations, and on June 5 was between second and third locations. No. 6: Four captures in 23 months, all within a 20-foot stretch of ledge, in 1950 on June 5 and 17, in 1951 on August 22, and in 1952 on May 1. No. 7: Four captures in one year, in 1951 on May 19, June 12, June 24, and in 1952 on May 21, all four locations within a 15-foot diameter. No. 8: Four captures in 23 months, in 1950 on July 5 (as a subadult), in 1951 on August 6 and 15, and in 1952 on May 28, all within a radius of a few yards at the pond rock pile. No. 9: Four captures in 13 months, on August 2 and 3, 1951, and May 28 and August 31, 1952. From the original location successive sites were 30 feet southwest, 20 feet south southwest, and 30 feet north. Young No. 1: (male) Five captures in 33/2 months; marked as hatchhng on July 13, 1949, and recaptured on June 1, 1950, 175 feet northwest down slope. Subsequent locations of this lizard, as an adult, were, in 1951, on August 21 and 24, and 1952 on May 1, 80 feet east, 80 feet east, and 70 feet northeast from the second location. No. 2: (male) Five captures in a little more than one year, all within a radius of a few yards at the pond rock pile, in 1949 on August 23, and in 1950 on June 7, July 23, August 19, and September 3. No. 4: (male) Four captures in 11 months all within a 30-foot stretch along the ledge, in 1950 on July 4, and in 1951 on May 6, 14, and 25. No. 5: (male) Four captiures in one year, in 1950 on September 4, and in 1951 on May 11, June 14, and August 21; the first and last locations were to- gether separated from the second and third, also together, by about 20 feet. No. 6: (male) Fotar captures in 13 months, in 1950 on April 19, June 5 and June 6, and in 1951 on May 14. All four locations were linearly distributed along the ledge, the second and third near together 30 feet north of the first and the fourth 30 feet south of the first. No. 7: (sex undetermined) Four captures in one month, on April 24, and May 2, 4, and 21, 1952, well scattered within a 70-foot diameter. No. 8: (female) Eight captures in 25 months, in 1950 on June 5 and 9, and in 1951 on May 25, August 15, and September 28, and in 1952 on April 24 and 26. All were within a 150-foot diameter, the first three all within 40 feet, the fifth and sixth near together but 35 feet north northeast from the first group, the last three all within a 90-foot diameter and all to the north of the first five. At least one shift probably was involved. No. 9: (female) Five captures in 28 months, in 1950 on April 21 and May 7, in 1951 on May 3, and in 1952 on May 2 and August 27. The first three captures were all at approximately the same location, from which the fourth was 60 feet north and the fifth was 130 feet east. No. 10: (female) Five captures in 24 months; in 1950 on June 5 and 13, and July 29, in 1951 on August 21, and in 1952 on May 28. From the original 112 UNrv'ERSiTY OF Kansas Publs., Mus. Nat. Hist. location successive captures were 50 feet west, 35 feet west northwest, 40 feet west, and 50 feet west. Less complete records of the movements of other individuals are included along with growth data, on pages 79 to 82 and 87 to 88. Sizes of home ranges are affected by the type of habitat. For instance, the pond rock pile approximately 70 x 30 feet, must have constituted the entire home range for the many individuals living in it, since it was surrounded by areas that did not provide suitable habitat. No less than 212 five-lined skinks were taken in this small rock pile area in four seasons, and it is obvious that many of these were occupying it simultaneously since a substantial proportion of the total were caught there in more than one year. This rock pile provided in particularly concentrated form the essential habitat re- quirements, such as an abundant and varied arthropod food supply, an almost infinitely large number of hiding places beneath and be- tween the rocks, basking sites, and flat rocks with damp soil beneath, suitable for nests. In open woods home ranges tend to be larger or, at least, more elongate. Scattered distribution of such habitat fea- tures as flat rocks and outcrops, stumps, logs, and glades with patches of sunlight, may induce an individual to extend its activities over a more extensive area. For some of the adult males for which largest numbers of records are available, showing repeated movements back and forth within a definite area which seemingly constituted a home range, movements of 275 feet, 225 feet, 170 feet, 165 feet, 150 feet and 130 feet, respectively, have been recorded. For one young which grew to the size of a subadult during the period covered by the records, movements within a 150-foot diameter were recorded. These individuals all had home ranges substantially larger than the average. It seems that in the five-lined skink there is no fixed size or shape for a home range, but that it varies within rather wide limits depending on age, sex, and perhaps individual peculiarities and on the presence and distribution of essential habitat features within the general area. Most of the young that were recaptured had grown to subadult or adult size, so that the movements they made as young cannot be separated from those made when they were full grown or nearly so. For 40, however, recapture records are available while they were still less than 56 mm. long. One of those was an exceptionally long movement of 215 feet, obviously involving a shift of range. For the other 39, the average movement was 34 feet, almost intermediate between the average movements of adult males and females. Ob- servations on recently hatched young have given the impression that they keep to narrowly limited areas probably only a few yards in Life History and Ecology of Five-lined Skink 113 extent at first. For instance, at various times several members of a brood of young have been observed foraging simultaneously but independently on the same 10-foot log, within a few feet of each other. For periods of up to more than a week they had failed to disperse any farther than this from the nest, although probably never returning to the nest itself after having left. In subsequent weeks, however, the young are likely to shift their activities from the immediate vicinity of the nest site to more favorable near-by areas, and gradually extend their ranges. By the time they are one- fourth grown they are ranging over areas larger than those used by adult females. Some of the shifts in range are probably forced upon individual skinks by changes in seasonal distribution of food, shelter and other requirements, causing them to abandon certain areas and invade others by gradual stages, without venturing far, at any time, into unfamiliar surroundings. Occasional individuals apparently get lost and undergo a period of wandering before they re-establish a home range. An individual venturing slightly beyond the border of its home range might lose its orientation and fail to return, especially if it left under conditions of stress, as when pursued by an enemy, or a rival of its own species. Several individuals originally captured in the vicinity of the quarry or nearby ledges, were subsequently re- captured at the pond rock pile more than 200 yards away. In these instances it may be that the lizard wandered from its home range along the ledge, and finding itself in thick woods, with nearly continuous canopy permitting insufiicient sunlight, and with few rocks for shelter, it continued down the slope to the lower edge of the woods, crossed a ditch, and a 100-foot stretch of grassland, and finally reached the exceptionally favorable habitat provided by the rock pile. The extent to which memory persists through the season of dormancy is little known, but great change takes place in the habitat during the colder half of the year when the lizard's activity is suspended. Even if the area is one that is free from gross disturbance by man or large animals, the changes occurring are so great that the area might be scarcely recognizable from the lizard's viewpoint. Herbaceous vegetation mantling the soil, at the height of its development in late summer, will have died, dried out and the leaves and stalks will have been matted down by wind, rain, and snow, and incorporated in the surface layer of soil by the next spring. Shrubs and trees having shed their leaves, present contours quite 8—3559 114 Untversity of Kansas Publs., Mus. Nat. Hist. different from those in autumn. Holes and crevices familiar as avenues of escape, will have been sealed, by the weatlier collecting and compacting surface debris. Less extensive changes are involved in the occasional blowing down of trees and dead snags, erosion of gullies, deposition of sediment and drift wood, and disintegration of logs. Many of the invertebrates which are the main food sources in late summer, are unavailable in early spring, being at different stages in the hfe cycle or annual cycle of abundance; and those kinds which make up the bulk of the spring diet likewise are often unavailable in fall. These changes in location of food supply, shelter, and other needs, and the seasonal change in microhabitat, breaking the established routine of conditioned responses to habitat features would seem to promote shifts in range after emergence from hibernation. The available records tend to bear out this supposition. Of the 15 skinks recorded as making long movements of more than 250 feet that almost certainly involved shift in range, only one was recaptured the same season; the other fourteen had passed one or more hibernations. In the course of the study approximately 30 individuals were re- leased or accidentally escaped at places other than the locations where they were originally taken. Some of these were young hatched in the laboratory, some were of unknown origin, their lo- cality tags having been lost before release while they were being handled in the laboratory, or escaped from defective cloth bags while they were awaiting processing or release, and some taken on remote parts of the Reservation or near-by land were deliberately released on one of the study areas with the idea that they would re- place skinks of the same sex and age, recently eliminated through an accident of trapping or handling. Ten were released in Skink Woods, ten at the pond rock pile, eight at the laboratory building, and two near Rat Ledge. In no instance was a transferred skink known to have found its way back to an original home range, al- though some might have done so with fairly short trips of only a few hundred feet, and the chances of recapturing them would have been good. Therefore it seems that homing instinct is either wholly lack- ing or but feebly developed. The incidence of recaptures was low, only four for the entire group, suggesting a tendency to wander away from the area of release before settling down on a home range. One young found on May 11, 1950, in the laboratory where it prob- ably had escaped, was released in Skink Woods, and was recap- tured three times in the summer of 1951, in what seemed to be a home range within 80 feet of the point of release. Another young Life History and Ecology of Five-lined Skink 115 of unknown origin released in Skink Woods on May 18, 1950, was recaptured six days later 160 feet away. Five hatchlings from a clutch of eggs incubated and hatched in the laboratory, were re- leased in Skink Woods on August 8, 1952. The following April two of them were recaptured, only 20 feet and 25 feet respectively, from the point of release. The movements and dispersal of this group from the point of release probably paralleled that of a typical brood dispersing from its nest after hatching under natural conditions. An adult male captured just ofiF the Reservation was released at the pond rock pile on May 15, 1952, and was recaptured there on June 2 and June 4. In general, skinks transferred from their original loca- tion seem soon to settle down in a new range if the habitat is favor- able, but establishment of a home range may or may not be pre- ceded by an initial period of wandering. Food Habits McCauley (1939: 151) examined contents of 25 alimentary tracts of E. fasciatus collected in Maryland as the basis for the most ex- tensive account of the food habits yet published. One tract con- tained a broken Eumeces tail, possibly that of the lizard that ate it, which had a recently broken stump tail. A half -grown skink con- tained numerous Eumeces scales, and McCauley interpreted this as indicating that it had fed on another of its own species or of E. laticeps. As no other hard parts of the assumed victim were in evi- dence, these scales may have been the lizard's own slough. (In the present study it was found that eating of the slough was far more frequent than cannibalism.) Arthropod prey included: 11 orthop- terans (4 undetermined, 3 unspecified grasshoppers, 2 gryllids, 1 blattid, 1 acridid); 10 coleopterans (7 undetermined, 1 each of rhynchophoran, cerambycid, carabid, staphylinid larva, elaterid adult and larva); 8 spiders; 5 pulmonate snails; 5 flies; 3 undeter- mined; and one each of lepidopteran larva and adult, ant, dragon- fly, thysanuran, and sow bug. In Ohio, Conant (1940: 31) noted food items consisting largely of grasshopper nymphs and small beetles. He found that in cap- tivity these skinks would eat mealworms, crickets, grasshoppers, spiders, roaches, and newborn mice, and a few individuals would lap egg from a mixture of chopped meat and eggs. One large male killed and ate a small common swift ( Sceloporus undulatus ) . Net- ting (1939: 162) mentioned newborn mice, birds' eggs and small hzards as possible prey, although stating that this species is mainly insectivorous. 116 University of Kansas Publs., Mus. Nat. Hist. Taylor (1936: 61) describing the feeding habits of Hzards of this genus wrote: "The food consists of a very extensive variety of insects and insect larvae, Arachnida and occasionally small crus- taceans. In a few specimens traces of plant material have been ob- served, but I regard this as being most probably of accidental in- troduction in the diet. Probably the most surprising fact about the diet of the forms examined is that ants are absent." In the present study of E. fasciaius, the trends in general bore out Taylor's find- ings concerning absence of ants from the diet, although three ants were found among more than 600 other food items. These three, one of them a larva, were of the two largest species among tlie many kinds of ants found in the area of the study. Most of these local kinds of ants are below the minimum size of prey ordinarily taken by the skinks. Colonies of small ants, Aphenogaster sp., for in- stance, are abundant in the soil beneath flat rocks in the same situa- tions where the skinks are found, and constitute most of the food of the small toads, Microhyla olivacea, which were abundant in tlie same habitat and microhabitat as the skinks, especially in tlie Skink Woods study area (Freiburg, 1951: 383). Burt (1928: 56) without citing specific records, stated that "The food of E. fasciatiis consists largely of insects and spiders," but in another paper (1928: 62) he listed contents of two stomachs, in- cluding a wood roach (Parcoblatta), a cricket (GryUus permsyl- vanicus), a grasshopper, and 2 spiders (attid and lycosid). Smith, summarizing the findings of other authors (1946: 350), stated that "The food consists of various small insects, insect larvae, earthworms, spiders, etc. Small vertebrates such as young lizards and mice are sometimes eaten." In a later work Smitli (1950: 188) altered this statement slightly: "The food consists of almost any small moving animal, including many kinds of arthropods and even small verte- brates." Many authors have mentioned predation on mammals by these skinks, but without citing specific instances, which must be rare indeed, for the smallest newborn mice seem to be near the maxi- mum size of objects that could possibly be swallowed by the largest adults of the common five-lined skink. Various early records and statements pertaining to predation on small vertebrates by five-lined skinks probably pertain in most cases to E. laticeps, which is much larger than E. fasciotus, and more powerful. Barbour (1950: 102) recorded stomach contents of an E. fasciatus collected in Harlan County, Kentucky, as consisting of 60 per cent Arachnida, 30 per cent adult Lepidoptera, and 10 per cent ants, by Life History and Ecology of Five-lined Skink 117 volume. Werler and McCallion ( 1951 : 250 ) mentioned that on two occasions these skinks in Virginia were seen to eat tenebrionid beetles and larvae. Webb (1949: 294) fed captive skinks with field crickets (Grtjlltis) and noted that the lizards tended to seize them by the pronotum, and then worked forward to the head, chewing vigorously to dis- able them. The seized crickets attempted to defend themselves by striking the lizards' faces and eyes with the cerci and tibial spines. Webb also oflFered his skinks newly hatched snails, Helix aspersa, which were noticed and fed upon when they moved. In one in- stance, he noted that a skink found a quiescent snail, and swallowed it after testing it with the tongue a few times. Mcllhenny (1937: 232) has published a remarkable account of observations on the foraging behavior of a large adult male skink (stated to be £. fasciattis but almost certainly £. laticeps) in southern Louisiana, which chmbed among vines on the side of a house and attacked nests of wasps, Polistes pallipes and P. bellicosus, shaking out the larvae, pausing to crush and swallow the few adults that lit on it and attempted, unsuccessfully, to sting. After many larvae had been shaken to the ground the skink descended and made a leisurely search, eating them in seemingly prodigious quan- tities. Several times it climbed back into the vines to shake out more larvae, and each time retrieved from the ground those it could find. After feeding to repletion it returned to its habitual shelter in a hollow live oak fifty feet from the house. In a two-week period, however, it returned frequently to raid the wasp nests in the vines, and eventually it had attacked all of the 32 nests that were originally present, completely destroying many of them. In the course of the present study direct observations on the food habits of skinks rarely could be made in the field. Most of those seen had been alarmed by the presence of the observer, and already had begun a dash for shelter. Others not suflBciently alarmed to take cover, were aflFected by an observer's presence, so that usually they ceased their normal activities and crouched attempting to conceal themselves or slithered nervously from one vantage point to another, on the alert for any sign of danger. On September 1, 1951, a young skink (30-35 mm. snout-vent length ) was discovered on the cement walk just outside the labora- tory building, holding a cricket ( Nemobius ) which evidently it had just caught. When I came out of the building, the skink, alarmed, ran about ten feet, holding the cricket by one leg. The cricket was still aUve but was nearly immobilized, except for twitching of its 118 UNrvERSiTY OF Kansas Publs., Mus. Nat, Hist, antennae and mandibles, and evidently it had already been shaken and battered. After maneuvering about the cement walk the skink ran through the open door into the building. Though seeming to be uneasy at my proximity it was still mainly intent on subduing and swallowing its prey. Following, I caused the skink to take alarm. It dashed back through the door to the walk outside and still carrying the cricket, it ran along the walk to tlie steps leading up to another building and climbed onto the first step where its uneasiness soon subsided. The cricket was remarkably large in proportion to the skink itself, being of approximately the same diameter, with a length nearly half that of the skink's snout-vent length. Nevertheless, in about five minutes the skink had swallowed it entire. As swallowing began, on the cement step, the skink was in bright sunshine of early afternoon. In less than a minute it seemed to become overheated, and dragged the prey back several inches into shadow. While swallowing was still in progress, it again ran forward till its anterior half was in sunshine, seemingly regulating its body temperature by these frequent shifts, A similar encounter between a larger juvenile and a cricket (Ceuthophilus) was observed on May 9, 1953, After I had stood for several minutes beside a rock ledge in woods, my attention was attracted by a rustling sound in dry leaves. The skink, emerging onto the ledge from a cavity beneath exposed hackberry roots had its head raised high and was darting about, peering into crevices and examining its surroundings with unusual animation. After several seconds the cricket hopped into view. Possibly it had been injured already, as it moved deliberately, with short hops. Instantly the skink darted in pursuit, following its erratic course persistently, as it made several hops. In a few seconds the skink caught the cricket, bit it vigorously, and battered it against the rock ledge with violent lateral shaking. Several times the cricket was knocked from the skink's jaws, but each time it was quickly retrieved. In a few seconds its struggles were subdued, but the skink continued to worry it, dropping it and retrieving it dozens of times. The skink seized the cricket by one of the large rear legs, which was snapped oflF with a sudden vigorous shake. The skink then dropped and lost the detached leg, and ran back to seize the cricket again. The performance was repeated with several other legs and the antennae, until most of the appendages were eliminated and the body was softened by continued biting and chewing, Then although the cricket was of body diameter almost as great as the skink itself, the lizard swallowed it head first, engulfing it with violent gulping Life History and Ecology of Five-lined Skink 119 movements. After the front end of the prey had entered the guUet, muscles of the throat and neck were brought into play in forcing it farther down. Swallowing movements were snake-hke, the liz- ard turning its head at right angles to the body to squeeze the morsel down. At the pond rock pile on May 7, 1952, a small adult male was watched as it moved about over the rocks. A lycosid spider {Pardosa lapidicina) carrying an egg sac was basking on an in- clined rock surface. Wlien the skink had come within a few inches, it made a sudden rush at the spider which escaped easily. As this common rock-living spider can move with almost incredible speed, skinks probably do not often catch them in the open. Captive skinks, in taking their food, seem to rely much less than some other lizards on movement of the prey as a means of detecting it. An active and hungry skink often failed to notice a spider or insect moving about on the opposite side of the terrarium a foot or more away. However, on many occasions, skinks moving about the terrarium and coming upon a motionles prey item have been seen to stop and examine it intently for several seconds, then grasp it, often in a tentative and hesitant manner, after testing it with the tongue. Sight and scent seem to be about equally important in prey recognition, each supplementing the other, and often function- ing simultaneously. As many of the animals preyed upon are secretive and would seldom be found in the open by day, it seems that much of the prey is found in hiding places — in leaf litter on the forest floor, beneath flat rocks or at their edges, and in chinks and crannies of decaying logs, stumps, and tree trunks. Some of the prey animals taken are of types that are more active and swift than the skinks themselves. Presumably the olfactory sense is the more important in detecting prey that is motionless or concealed. Steb- bins (1948:202) studied the nasal structure of Eumeces, and com- pared it with that of other lizards. He concluded that the exten- sive mucus-secreting and olfactory surfaces suggest relatively eflicient humidification of inspired air and efficient olfaction in Lizards of this genus. In captivity five-lined skinks thrived when provided with ample moisture and shelter and food and kept within the proper temperature range. The reactions of these captive skinks to various small animals introduced into their terraria pro- vided clues as to their food preferences, but also were misleading in some instances. On many occasions hatchlings and young of various sizes were kept with adults of both sexes and subadults, but no instances of cannibalism were ever recorded in captivity. No 120 Uxn'ERSiTY OF Kansas Publs., Mus. Nat. Hist. hostility was seen except between adults, mainly in the breeding season. Young of the little brown skink, Scincella laterale, kept with adult E. fasciattis, and small enough to be eaten by them, like- wise were unmolested. Small snakes such as Diadophis, Carphophis, and Storeria placed in terraria with the skinks evoked no strong reaction. Occasionally mild avoidance reactions were aroused but the skinks were never seen to display any hostility and readily became accustomed to such cage mates. Mealworms, the most readily available food for the captive skinks, were generally accepted by those that were hungry and su£Bciently warm, but were taken with little enthusiasm. They were seldom noticed unless the skinks were within a few inches. Skinks sometimes tested them with their tongues and examined them intently then moved away with- out eating them. Earthworms, offered on several occasions, were not eaten. Harvestmen, seemingly of the same kind as those found in scats, were ignored by some captive individuals and taken by others but with some signs of distaste. Ants were ignored. Scara- baeid beetles, that seemed small enough to be eaten, were attacked unsuccessfully, as they were too heavily armored to be crushed in the skinks' jaws. Wasps (Polistes) placed in terraria were avoided, as were carabid beetles and reduviid bugs. A spider placed in the terrarium usually aroused one or more skinks to animated pursuit, as soon as it moved. Even spiders that seemed to be too large to be swallowed were sometimes pursued and attacked. Occasionally freshly killed prey was taken, especially spiders and wasp larvae. Of invertebrates minute forms are not taken, while certain ants, and various others of the kinds of insects most common on the study areas and often found rather closely associated with the skinks and using the same shelters, were never represented among the re- corded food items. Carabid beetles (Brachinus, Calosoma, Lebia, Harpalus, Pasimachtis) , and reduviid bugs (MelanoJestes, etc.) seemed to be especially abundant and available, but habitually avoided possibly because of their noxious qualities. Diptera were entirely absent from the sample in the present study — they and many other insects are so much quicker than the skinks that ordi- narily these insects cannot be caught. Foliage-living insects and those that are strong and persistent fliers, are rarely available as prey. A total of 738 food items were recorded in the present study. Arachnids with 360 items, and insects with 319, together made up 92 percent of these food items. There were 334 spiders ( most were not definitely identified, but four were thomisids, 40 were lycosids, and 79 were salticids, the latter group including 27 of the genus Life History and Ecology of Five-lined Skink 121 Phidippus); 26 harvestmen (Leiobunum vittatum and others); 149 orthopterans (51 ceuthophilid crickets, 31 gryllid crickets, 27 tet- tigoniid locusts; 17 unspecified, 14 roaches, 9 locustid grasshop- pers); 80 indeterminate insects; 39 beetles (mostly carabids and scarabaeids within a narrow size range ) ; 19 larvae ( 13 lepidopteran, 2 coleopteran, 1 ant, 3 indeterminate); 2 ants (Camponotus hercu- laneus and C. castaneus); 2 wasps; 1 moth; 1 centipede; 59 snails (31 indeterminate, 18 Gastrocopta armifera, 8 Retinella electrina, 1 Strobilops labyrynthica, 1 Hawaia minuscula) ; 23 sloughed skins of the skinks themselves; 2 skink eggs; and 2 skink hatchlings. This sample is based on combined sets of data from analysis of stomach contents and of "scats." The two sets of data present some- what divergent trends, and perhaps neither is adequately represent- ative of the food habits in the geographic area represented. A total of 620 food items found in scats represented an average of 1.67 items per scat, whereas in 80 stomachs containing food the average was 1.44 items per stomach. Of the skinks killed and dissected more than half had empty stomachs. Many of them were, however, found inactive in shelter so that it was obvious that they had not foraged recently. Many were not killed immediately and they may have had time to digest any food in their stomachs. Determinations of the prey down to species were possible in rela- tively few instances; usually only the family or the order could be determined. Those who have attempted food habits studies of in- sectivorous small vertebrates will appreciate the obstacles encoun- tered. The invertebrates available to the skinks in the area of the study included many thousands of species. A large number of these species, perhaps the majority, belong to groups still not thoroughly studied, so that their taxonomy is in a state of confusion. Ordinarily the prey is crushed in the jaws and battered on the ground before ingestion; diagnostic structures are often broken or lost, making identification far more difficult. Prey animals taken are often in immature or larval stages which lack the distinguishing features presented by adults. Even the combined efforts of a team of spe- cialists on each of the prey groups involved probably would not have sufficed to obtain generic and specific identification of every item found. In the present study, however, all determinations were made by the writer, with the aid of the small reference collection at the University of Kansas Natural History Reservation. The 80 specimens used for stomach contents analysis nearly all came from localities off the Reservation, but all within a ten-mile radius thereof. A dozen localities were represented by these speci- 122 UiNTVTERSITY OF IC\NSAS PUBLS., MuS. NaT. HiST. mens, and within each locahty specimens were taken in somewhat different situations. Therefore the stomach contents analyzed rep- resents a wide range of ecological conditions, including many dif- ferent microhabitats. All the stomach contents were collected in late April, May, and June — within the first half of the skinks' active season. Trends might be expected to differ in late summer and fall. The food items from stomachs included: 38 spiders (8 of the salticid genus Phidippus, 5 lycosids, 4 thomisids, and the remainder unspecified ) ; 15 insect larvae ( 7 of them lepidopteran and one ten- tatively identified as an ant, Camponotus castaneus, the rest unspe- cified); 13 unspecified insects; 10 crickets; 9 roaches; 9 snails (5 of them Gastrocopta armifera); 7 beetles; 4 sloughs of skinks; 3 grass- hoppers; 2 grouse locusts; and one each of cave cricket (Ceutho- philus ?), ant (Camponotus castaneus), moth, centipede, sow bug, and egg of a skink. The egg was probably laid by the female that ate it, since she was found brooding an unusually small clutch of only three eggs. The condition of food items found in stomachs varied greatly. Some were nearly intact, while others were fragmentary and rep- resented by only a few of the more durable and indigestible parts. The larvae of various insects found in stomachs examined are es- pecially noteworthy, since but little comparable material was found in the much larger group of items identified from scats. The scatological material was even less satisfactory than the stomach material in providing determinable food items. The scats of these skinks are, roughly, 10 to 20 mm. long and two to four mm. in diameter, usually cylindrical and almost straight, and capped at one end with a white chalky deposit of uric acid. Superficially they have some resemblance to bird droppings, but are different in tex- ture. The uric acid deposit is loose and crumbly, and much less compact than that with bird feces, and the food residue is much less completely disintegrated than is similar material in feces of birds. Common small snakes which might produce feces of similar size, include the ring-necked snake (Diadophis punctatus), the worm snake (Carphophis amoenus), and DeKay's snake (Storeria dekayi), but their feces have a much higher moisture content, lack the defi- nite shape of the skink scats, and ordinarily do not contain readily recognizable residue of the prey. The six other species of lizards on the Reservation, the collared lizard (Crotaphtjtus collaris), brown skink (Scincella laterale), prairie skink (Eumcces septentrionalis) , Sonoran skink (E. obsoletus), six-lined racerunner (Cnemidophorus sexlineatus) and glass "snake" (OpJiisaurus attenuatus) might pro- Life History and Ecolcxjy of Five-lined Skink 123 duce scats indistinguishable from those of the five-hned skink. However, none of these hzards except the relatively rare and secre- tive brown skink, occurred in either of the two situations where most of the scats were collected and it is highly improbable that the scat collection included any material from species other than the five-lined skink. The scats consist mainly of chitinous fragments of arthropod prey. Usually the prey fragments are so well comminuted, mixed, and scattered that reconstruction is difiBcult. Degree of disintegration diflFers greatly, depending not only on the type of prey eaten, but probably also on the condition and temperature of the lizard, and the amount of other food in its digestive tract. Arthropods which have recently undergone ecdysis and have the exoskeleton still thin and soft are no doubt digested much more completely than those that have more heavily sclerotized parts. In spiders the chelicerae are more resistant to digestion than are other parts of the exoskele- ton, and frequently appear, intact or nearly so, in the scat contents. The fangs being even more resistant, were sometimes found sepa- rately when no other cheliceral parts were recognizably preserved. Frequently large fragments of the carapace, with some of the eyes or all of them, were found. Spider abdomens sometimes were dis- tinguishable, but were collapsed and compressed. Spider legs con- spicuous in most of the scats, were so broken, tangled, and distorted that they were of little diagnostic value. In harvestmen, dorsal shields were nearly always fairly intact; but only small fragments of the elongate slender legs were found and they were mostly broken off when the attacking skinks battered the phalangid against the ground before swallowing it. The horny outer wings of crickets, roaches, and beetles usually were in recognizable though fragmen- tary condition. Occasional heads of insects often were found fairly intact. Insect legs were sometimes intact, sometimes broken into sections or crushed and fragmented. The thorax was usually rep- resented by scattered fragments of chitin, and the abdomen by the separate chitin bands of each body segment. Shells of snails were sometimes found nearly intact in the scats, although showing the effect of the digestive juices in their extreme brittleness. In other instances all that remained of the shell was the inner columella, and small scattered fragments. Certain of the items eaten were probably so thoroughly digested as to leave either no hard parts at all, or minute and nondescript parts that were not recognized. The common small slug Deroceras laeve, for instance, would seem to be just as suitable and available 124 UNn^RSiTY OF Kansas Publs., Mus. Nat. Hist. for food as the various kinds of snails, but it was not recorded in either stomachs or scats. HaWng no hard parts except the vestigial internal shell, it probably would not be recognized in scats, even though it had been eaten. Various insect larvae, having thin outer cuticles and virtually no hard sclerotized structures except in the head, likewise probably would leave no recognizable parts. Molted skin of the slcinks themselves seemed to be httle altered by the digestive processes. The collection of 371 skink scats originated mainly from two places on the Reservation nearly three-quarters of a mile apart, the pond rock pile and an old wooden bridge across a ravine. On the weathered planks of the bridge, the scats were conspicuous and could be easily gathered in quantity. At the pond rock pile, where skinks were especially abundant and were intensively studied, their scats were frequently noticed on the large rocks where they hunted and basked. A third smaller collection of scats was made in the vicinity of the laboratory buildings and adjacent rock walk fre- Table 16. Frequency of Occurrence by Months of Various Types of Prey in a Collection of 371 Scats of Eumeces fasciatus. May (and April) June July Aug. Sept. Total Spider unspecified 32 10 7 32 18 1 7 4 6 1 2 16 5 3 1 ll' 100 31 18 16 14 31 16 17 6 2 11 10 7 4 2 "2" 1 2 "2" 190 salticid 71 lycosid 33 Harvestraan (phalangid) 26 Orthopteran unspecified 18 cricket (ceuthophilid) 50 cricket (gryllid) 2 3 20 grouse locust 24 grasshopper 6 roach 1 4 2 13 "l" 1 5 Beetle 31 Ant 1 Wasp 1 1 3 2 1 1 45 12 1 8 8 6 ...... 5 1 1 6 1 2 Caterpillar 3 Other insects 8 1 6 3 67 Five-lined skink slough 19 hatchling 2 Snail unspecified 3 6 2 1 6 29 Gastrocopta 11 Retinella 1 8 Total 70 104 53 344 45 616— Life History and Ecology of Five-lined Skink 125 quented by a few skinks. A small number of additional scats were collected elsewhere on the Reservation, but ordinarily the scats were so inconspicuous in the woodland situations where skinks occurred under typical habitat conditions, that few were found. The rock pile, bridge, and vicinity of buildings are not typical of the species' habitat and might oflFer somewhat different choices of prey items. The 30 scat collections were made in 1951 and 1952. Seasonally, the sample of scats overlapped but httle the sample of stomach contents, and was concentrated in the latter half of the growing season. The distribution by months was as follows: April-2; May- 38; June-60; July-29; August-213; September-26. Most of the scats probably were deposited within a few days of the time they were collected, because scats disintegrate and disappear rapidly in the field where they are exposed to rain, wind and dung-feeding insects. No clearly defined seasonal trends are revealed in Table 16 but the monthly samples, except that for August, are scarcely adequate for this purpose. Approximately equal numbers of scats were col- lected at the two main stations, the pond rock pile and the bridge, but some kinds of items were unequally represented in the two samples. Table 17. Comparison of Freqxxency of Occxjrrence of Various Food Items in Two Different Small Areas, Based on Scat Analysis. Total from both collecting stations Percentage of total in bridge sample Percentage of total in pond rock pile sample Spiders (all) salticids Phidippus audax. Phidippus sp lycosids harvestmen , ceuthophilids , grouse locusts crickets snail Gastrocopta , Retinella 292 67 16 3 33 28 39 25 26 34 11 6 63.3 79.2 100.0 36.3 57.1 30.8 92.0 42.3 61.9 91.0 50.0 36.7 20.8 100 63.7 42.9 69.2 8.0 67.7 38.1 9.0 50.0 Spiders, harvestmen, and snails were well represented in both samples. In the bridge sample, salticids (especially Phidippus audax), grouse locusts, and the snail Gastrocopta were more numerous. In the rock pile sample lycosids, and especially ceutho- philid crickets were more abundant. The ceuthophihds were not- 126 University of Kansas Publs., Mus. Nat. Hist. ably numerous among the rocks, and many of them were caught in the wire funnel traps placed there for skinks. Little is known concerning the quantitative food requirement of any kind of lizard. Five-lined skinks fast for at least half the year during the period of dormancy, from September to April. When they emerge from dormancy in spring most of them are plump and appear to have lost little weight in the course of their long fast. In the season of activity, obviously the quantity of food consumed fluctuates according to temperature and activity of the lizard. Most of the prey taken falls within a fairly narrow size range. The prey ordinarily is swallowed entire or nearly so. This imposes a definite upper size limit. The skink of course lacks the ophidian capacity to ingest relatively enormous objects. The mental symphysis and pectoral girdle would prevent ingestion of an object much larger than the skink's body diameter, but soft-bodied and flexible ar- thropods of body diameter approximately equal to that of the skink may be ingested. Typical food items are of such size that from one to three of them fill the stomach to capacity. On one occasion, in an attempt to feed a brood of young recently hatched in the labora- tory, I dropped into their jar a mass of newly hatched house spiders (Theridion tepidarioruin) . As these minute spiders swarmed over and around the skinks, the lizards gave little heed to them ex- cept occasionally to jerk or scratch in irritation. One skink, how- ever, was seen to snap up a spider which ran near its snout. The adult female Theridion from the same web was then introduced into the skinks' jar, although it seemed too large prey for tliese small lizards, as its abdomen was fully as large as their body diam- eter. When it ran, the hatchling skinks immediately became alert and several chased it biting at it in frantic excitement. They had difficulty in grasping its smooth rounded surface, but eventually one did catch it and eat it. Full-grown mealworms averaging 26 mm. in length, and approximately .11 grams, are somewhat smaller than the usual prey of adults. In captivity hungry adult skinks took from one to nine such mealworms at a meal. However, they could not be induced to feed daily over periods of weeks, even when kept at high temperatures. Over a period of 64 days an adult male kept at approximately 80° F. in the daytime and 10 to 15 degrees lower at night, ate a total of 30 mealworms, which, in the aggregate, weighed approximately 42 per cent of his body weight. In 35 days under the same conditions an adult female ate 24 mealworms, ap- proximately 32 per cent of her body weight. Life History and Ecology of Five-lined Skink 127 Fig. 26. Map of University of Kansas Natural History Reservation showing locations of the four study areas ( shaded ) where most data on five-lined skinks were obtained. Predation and Parasitism Escape Reactions Like other members of the family Scincidae, Eumeces fasciatus tends to be secretive in its habits and it depends on concealment rather than speed, aggressive behavior, or noxious qualities to es- cape its enemies. As compared with lizards in general, or with other members of the genus Eumeces, five-lined skinks are rela- tively unspecialized in their behavior, and retain a good deal of versatility. While primarily terrestrial, they are able to burrow and climb. Their reactions toward prey and natural enemies vary greatly according to circumstances. They are less secretive than many other kinds of skinks. Never- theless the numbers active on the ground surface at any one time, even under the most favorable weather conditions, probably are 128 UNrvT^\siTY OF Kansas Publs., Mus. Nat. Hist. only a fraction of the total population. For instance, in two or three hours of intensive search in Skink Woods, in which almost every square yard of the area was inspected, a dozen skinks constituted an unusually good catch. Seldom were as many as 20 seen — and most of these only when uncovered in tlieir hiding places. At the pond rock pile, often half a dozen or even more could be seen simul- taneously or within the course of a few minutes, as they basked or darted about over the rock surface. These, however, represented only a small part of the number known to occur in the rock pile, which could be observed in its entirety from one spot. At other times, especially in late summer and early fall, even when weather seemed favorable, cursory search of each of the study areas failed to reveal a single individual. Presumably at such times the ma- jority of individuals of the dense population were sheltered deep underground in relatively inaccessible hiding places. Others which escaped attention may have been climbing on tree trunks or logs, or may have been foraging on the ground but close to hiding places into which they darted undetected. The habit of "freezing" in response to a potential danger is commonly noticed in these skinks, and usually it is effective in concealing them. Having elongate bodies and short limbs, five-lined skinks are not especially swift of foot, but the jerkiness of their movements pro- vides compensatory elusiveness. One sufficiently warm to be fully active is nervous in its actions. Even when resting or basking it is likely to shift its position frequently, fidgeting, blinking, and panting, obviously on the alert for any sign of danger. In moving about, it usually progresses only a few steps at a time, witli frequent pauses sometimes only a fraction of a second in duration. These numerous stops allow the animal to examine the terrain immediately ahead of it, and perhaps avoid blundering within reach of a lurking enemy. Ontogenetic change in the color pattern is of significance in connection with the secretive habits. The red facial suffusion of the breeding male renders him more conspicuous in his natural sur- roundings, but this bright color is ephemeral. It is developed as a warning, for display to other males. Otherwise, in the adult male the color of dull brown is inconspicuous in its natural sur- roundings, usually against a background of leaf litter, dead stems, and soil. In the juvenile the contrasting pattern of dark brown ground-color, five longitudinal light stripes, and a vivid blue tail, is far more conspicuous. The young skink might seem to be handi- capped in its chances for survival by tliis conspicuousness. How- Life History and Ecology of Five-lined Skink 129 ever, in snakes it has been shown that a vivid striped pattern, characteristic of forms that are fast moving and Hve in dense vege- tation, serves to conceal motion, and aid its possessor in confusing and eluding pursuers. The young skinks, being far more active than the adults, may use the striped pattern more eflFectively in this way. Often when a young skink is startled in its natural sur- roundings, and takes to cover, the observer does not see its outlines at all, and is conscious of it only as a flash of blue. On many occasions, while walking in the woods, I have had my at- tention attracted by a faint rustling of dry leaves, and have received such a fleeting impression of the flashing blue tail as to be uncertain whether or not I had actually seen a skink, until, raising a flat rock or other shelter, I found that one actually was present, con- cealing itself in the nearby hiding place. The erratic movements of a frightened skink that is warm and fully active, make it ex- ceedingly elusive. With sudden lashing movements of its heavy tail and hindquarters, it may flip its body about, facing first in one direction and then in another, as it pauses before or after a rush for shelter. The sudden reversals of direction are so confusing to the pursuer that the skink may often escape by hiding after a few seconds of pursuit, even though the situation provides no shelter where the lizard is entirely secure. The tail-flip described is characteristically given at the instant the lizard reaches shelter such as a crevice, or hole, and just before it disappears. By the in- stantaneous pivoting of its body, throwing its tail in an arc, in the direction of its original course, the lizard creates the optical illusion of having moved beyond the point where it has taken to shelter. The peculiar writhing movements of the tail of juveniles that are moving about in the open accentuate the conspicuousness of the vividly colored tail, and suggest that this conspicuousness may be advantageous to the lizard in serving as a decoy to catch the attention of predators and distract them from the Hzard itself. In hatchlings the mortality rate is high. Tails are broken frequently in those that survive, suggesting that the tail may be useful in diverting enemies from the lizard itself. Among 121 young of the smallest sizes, (snout- vent lengths in the range of 23 to 29 mm. ) 7.4 percent already had broken tails ( not including, of course, those in which the tails were broken while the skinks were being cap- tured). In slightly larger young, those in the 30-34 mm. range, perhaps averaging one month old, nearly one-fourth had lost their original tails. In those in the 35-55 mm. size class, mostly one to three 9—3559 130 UNrv'ERSiTY OF Kansas Publs., Mus. Nat. Hist. months old, about half have already lost parts of their original tails. In those that are in the size group 65-69 mm. normally attained at an age of a year, approximately three-fourths have regenerated tails, and in adults the proportion with unbroken tails is even smaller — down to 16.5 percent in females of more than 75 mm. snout-vent length. In adults die incidence of broken and regen- erated tails is slightly higher in females than in males. Defense of nests and sluggishness in the females during the time that they are excavating the nest burrows and guarding their eggs may result in their tails being broken more frequently. Tree-cHmbing is a common means of escape and it is curious that many of those who have described the habits of E. fasciatus have either failed to note it at all or have minimized arboreal habits. Taylor (1936: 59) cited two instances of tree-climbing but stated: "Only rarely is this form seen in trees, at least in the western part of its range." Conant (1951: 30) stated: "They seldom chmb trees, contrary to the habit of laticeps and inexpectatus." Hudson (1942: 42) mentioned seeing an adult that escaped by climbing the side of a hollow tree in southeastern Nebraska. In the present study, tree-climbing as a means of escape was ob- served frequently, probably more than two hundred times in all. It was characteristic of both sexes and all ages, and was one of the commonest responses to danger. In summer when skinks were fully active, they usually moved too rapidly to be caught by hand either in the open or where they were uncovered when I turned over rocks or other shelter. To obtain specimens in any numbers at such times, an understanding was essential of the somewhat stereotyped behavior pattern involved in their escape by tree-climb- ing. A skink that was alarmed in the course of its foraging or basking on the ground litter was likely to run directly to the near- est tree trunk, often a distance of several or many yards, and start up it, instantly disappearing to the far side of it. The trees climbed were usually small, two to eight inches in trunk diameter; however, in the second growth forest where the study was made, large ma- ture trees were relatively scarce. Having started up the tree trunk and concealed itself on the side opposite from its pursuer, the skink usually stopped one to five feet from the ground and waited quietly for the danger to pass. A vine of Virginia creeper, poison ivy, grape or moonseed, or a shrub such as gooseberry, providing screen- ing foliage at the base of the tree trunk, furnished the type of shel- tered situation that the skink was most likely to choose as a stopping place. The most efiFective technique for catching the lizard was to Life History and Ecology of Five-lined Skink 131 move slowly around the tree trunk at a distance of at least 20 or 30 feet and look for the Hzard clinging to it. Having located the lizard, the collector might take careful note of its position, then return to the opposite side of the tree and approach, unseen, to close range to make a sudden grab around the trunk. This ruse often succeeded; more frequently it failed, because of the lizard's adroitness in dodging, or failure of the collector to gauge its posi- tion accurately, or a slight shifting of its position between the time it was seen and the time when an attempt was made to catch it. The response of the lizard to the unsuccessful attempt to seize it depended on whether or not it was touched, and in which direction it was driven. It might drop to the ground and burrow into leaf litter or dash away to other shelter, or it might stay on the tree trunk and spiral rapidly upward out of reach. Because of the squirrel-like tendency to keep the tree trunk between it and the pursuer, the skink usually could be relocated only after some ma- neuvering. Having climbed the tree trunk to the bases of the main branches, the skink usually showed little inclination to move out along them but tended to hide in the crotches or to spiral back down the trunk. Often a long stick or pole was used effectively to drive a skink back down the trunk by touching or pushing it on the upper side. A skink maneuvered to the lower part of the tree trvmk was never loath to leave it in a dash for other shelter, which might be another tree trunk nearby. In moving downward or horizontally on a tree trunk or limb, a skink allows its heavy tail to bend down- ward from its own weight. The tail probably handicaps the lizard's climbing to some extent, and those with short regenerated tails have an advantage. The following extracts from my field notes are selected as typical illustrations of the climbing habit as a response to danger. September 15, 1948. A skink darted across the trail in front of me, to a tree 18 inches in diameter and climbed to a height of five feet where it stopped. Each time that I moved to approach and examine it, the skink was disturbed, and darted jerkily higher up the trunk until it was well out of reach at a height of about ten feet. May 2, 1949. Seeing an adult male skink lying in the open, I attempted to stalk it, but it became alarmed, ran to a shagbark hickory about six inches in diameter, and soon had climbed to a height of 25 feet. June 4, 1949. Juvenile, basking a few inches above ground on trunk of an elm ten inches in diameter, took alarm at my approach, and climbed rapidly out of reach, where it concealed itself in thick foliage. June 22, 1949. Movement two feet above ground on an elm sapling at- tracted my attention; an adult male and a juvenal skink were clinging to the trunk only a few inches apart, and neither moved as I approached and ex- 132 University of Kansas Publs., Mus. Nat. Hist. amined them from a distance of less than three feet. The conceahnent af- forded by numerous short twigs with thick foliage apparently caused them to feel secure. September 21, 1949. A juvenile was noticed climbing eight feet above the ground on a locust trunk. As I approached the sldnk continued upward to a height of approximately 15 feet above the ground where it disappeared around the trunk and could not be relocated. July 7, 1950. A nearly grown juvenile ran to an elm sapUng four inches in diameter, and chmbed up out of reach. When the skink reached the main crotch, it turned facing downward alertly. By reaching up with a long stick and poking it on the hindquarters, I succeeded several times in chasing it part way down the trunk, but each time it ran back up to the crotch and returned to the same position. July 26, 1950. A hatchling uncovered beneath a flat rock ran to a nearby oak tree about four inches in diameter and climbed to a height of five feet before it was caught. An adult female seen foraging in the open ran to a dead shrub and climbed one of the stems, inclined at an angle of about 45°. As- cending this stem she was unable to get more than three feet above the ground, and was easily captured. Another adult female seen foraging in the open ran to an oak about three inches in diameter, climbed rapidly to a height a little more than a foot above the ground, and concealed herself under the stem of a poison ivy vine twined about the tree trunk. July 27, 1951. A female brooding her eggs dashed out of the nest when the flat rock covering it was Ufted, ran 15 feet to a hickory sapling and climbed it. May 1, 1952. An adult male found beneath a rock ran to a small tree ten feet away, climbed up on the opposite side, and stopped about a foot above the ground. My first attempt to seize it failed and it ran around the trunk and stopped at a height of four feet. The next try was hkewise imsuccessful, and the skink dropped to the ground and burrowed into leaf litter. May 15, 1952. An adult male startled as it basked in a patch of sunUght in thick woods, dashed 25 feet without stopping, to an osage orange tree and disappeared behind the base of the trunk. Moving to the far side of the tree I located the skink clinging to the trunk two feet above the ground. My at- tempt to catch it failed and it spiralled up the trunk to a height of ten feet. When I poked at it with a stick, it crouched close to the trunk allowing the stick almost to touch it, then it spiralled down the trunk and could not be relocated. June 23, 1952. When I struck the trunk of a partly dead ailanthus tree with a brush knife to determine whether it was hollow, a juvenile darted out of a cavity five feet above the ground, ran farther up the trunk, and disappeared into another small hole. An adult male was seen running across the vertical wall ot a building, cfinging to the rough asphalt siding. When it was alarmed it ran to a crevice and hid. A more unusual escape-reaction was observed on May 25, 1952, at Tonganoxie State Lake, by Sydney Anderson, who recorded that a skink, alarmed by him at the edge of the water dived and hid among submerged rocks. Similarly, Boyer and Heinze (1934: 194) record of this species, in Jefferson County, Missouri: "When pur- Life History and Ecology of Five-lined Skink 133 sued they do not hesitate to take to the water and are very agile swimmers over short distances at least." Parker (1948; 25) wrote that in western Tennessee jasciatus sometimes showed a preference for habitat in the vicinity of water, and, if other concealment was not available, it would usually take refuge in the water. Natural Enemies Little is known concerning the kinds of predators that destroy five-lined skinks, or their importance in its ecology. In studies of the food habits of various predatory birds and mammals, workers often have been interested chiefly in items of direct economic bear- ing, and have tended to lump as "lizard" or "reptile" material that might have included Eumeces jasciatus. I have been able to find only a few specific references to predation on it. Nevertheless many kinds of predators probably utilize it as food, at least occasionally. Owls probably seldom have opportunity to prey on these skinks, which are not known to be active after dark. Nesthng broad-winged hawks observed in 1954 were found to have eaten an adult and a subadult five-lined skink on June 13 and June 23. The Cooper's hawk and red-shouldered hawk also are probable predators as both are known to feed upon small reptiles. Mammalian predators which might be expected to take skinks occasionally include the red fox, gray fox, bobcat, mink, weasels, skunks, opossum, armadillo, moles, and shrews. Snakes, especially those of the genera Elaphe, Lam- propeltis, Cemophora, Micrurus and Ancistrodon, may include some of the chief predators on the skink. Certain larger lizards also may prey upon it. Of these several potential predators, only the opossum, armadillo, and snakes {Elaphe obsoleta, E. guttata, Lampropeltis triangulum, L. calligaster, L. getulus, and Ancistrodon contortrix), Sonoran skink and the greater five-lined skink (in confinement) have actually been recorded as preying on Eumeces fasciatus but cir- cumstantial evidence has been obtained for the mole (Scalopus aquaticus) and short-tailed shrew (Blarina brevicauda). The short-tailed shrew may be one of the major predators on the skink. This shrew prefers the same habitats and occurs throughout the skink's extensive range. Like the skink, it is a characteristic in- habitant of the hardwood forests of the eastern United States, but its range extends farther north and west. A high proportion of the skinks examined had scars, usually on the sides or dorsal surface of the body, or of the tail near its base — wounds which must have been made by a small, sharp-toothed animal. For example, in May 134 University of Kansas Fuels., Mus. Nat. Hist. 1951, eighteen per cent of 155 skinks captured on the study areas had such scars. The incidence seemed to vary according to age and possibly sex; the scars were present in 22.9 per cent of the adult males, 25.5 per cent of tlie adult females, and only 9.8 per cent of the yearlings (these three groups being represented by appro.xi- mately equal numbers in the sample). As the scars are more or less permanent, adults could be expected to show a much higher incidence than young. Females, being inclined to stay in their nest burrows and defend them against small predators, may receive more wounds than the males, which are quicker to escape. None of the invertebrates present on the study area is sufficiently large or powerful to inflict such wounds, and none of the birds, reptiles, or amphibians has a dentition capable of producing them. The wood mouse (Peromyscus leucopiis) is the most abundant small mammal in the skink's habitat; other rodents present in relatively small num- bers include the prairie vole ( Microtiis ochrogaster ) , harvest mouse (Reithrodontomys megalotis) and pine vole (Microtus pinetonim) . Both voles and harvest mice have been known to kill skinks caught in the same traps with them, but individuals experimentally placed with skinks in captivity have failed to molest them and it seems likely that the attacks in traps were motivated by extreme hunger or self defense. The irregular scars from lacerated wounds charac- teristic of the skinks bear Httle similarity to rodent bites, in which the long, sharp-edge incisors make slit-like punctures. Other small mammals abundant in the places where skinks were studied were the insectivores: the common mole, short-tailed shrew, and least shrew {Cryptotis parva). On one occasion when a large five-lined skink was put in a ter- rarium with a recently captured short-tailed shrew, each displayed strong aversion for the other. The skink crouched, attempting to conceal itself in the end of the terrarium farthest from the shrew, and resisted efforts to drive it toward the shrew. In exploring the terrarium the shrew several times sensed the skink's presence, and then scampered away in frantic haste. The skink also rushed away several times when the shrew came close enough to disturb it. Three days later, when the shrew had become accustomed to the terrarium, the test was repeated, with different results. The shrew, having finished the food left for it, was noticed moving about the terrarium, sniffing and testing objects with its tactile snout, ob- viously hungry and searching for more food. The skink was then dropped near it. In a few seconds the shrew sensed the skink's presence and pounced upon it, and bit hard on its back. The skink Life History and Ecology of Five-lined Skink 135 reacted with a violent flexure of its body which caused the shrew to release it instantly, and both rushed away in opposite directions. After a few seconds the shrew located the skink again, and moved up to it with little hesitation but with nervous alert sniffing, and delivered another quick bite after which the two separated as be- fore, the skink showing signs of injury. Soon the shrew attacked a third time, and bit the skink's tail severing it near the base. As the skink rushed away, the detached tail performed lively squirming movements, but the shrew seized it, held it down, and began to eat the exposed flesh on the broken end as the tail writhed. After rapid nibbling it would drop the tail, and leaving it temporarily would explore the terrarium. Several times on these trips it en- countered the skink and renewed its attack. As death of the skink seemed imminent, it was then removed, and it survived with no apparent ill effects. The wounds inflicted by the shrew bore close resemblance to those noticed on skinks in the wild. It seemed al- most certain that Blarina had inflicted most of these wounds or all of them. On subsequent occasions several other captive shrews that were tested, quickly killed and ate skinks that were introduced into their containers. The least shrew, Crtjptotis, likewise occurred in all situations where skinks were taken, and in some localities was more abundant than the larger Blarina. Bites inflicted by these two kinds of shrews might be indistinguishable, but because of its larger size, Blarina would seem by far the more formidable enemy. Reynolds (1945:367) found E. fasciatus to be the most frequent reptile in a collection of opossum scats from Missouri, with two occurrences in 100 fall scats and ten occurrences in 100 spring scats. Sandidge (1953: 98 and 101) recorded one of these skinks among numerous other items identified from stomach contents of sixty-six opossums. Probably the opossum is a frequent predator on this skink. Although no specific instances were obtained on the area of the study, flat rocks a few inches in diameter frequently have been found flipped over, larger ones and those solidly anchored in the ground have been found partly undermined by opossums scratching away the loose dirt at their edges. The rocks found disturbed by opossums were typical of those used as shelter by the skink. On many occasions wire funnel traps set for skinks and other reptiles along hilltop rock ledges were found to have been disturbed, either shifted in position or with their rock shelters removed, or rolled downhill or broken open. Similarly, heavy flat rocks used to cover pitfalls, to protect the small animals falhng into them from predators, often were found 136 University of Kansas Publs., Mus. Nat. Hist. to have been shifted somewhat, or completely removed. When such raids became frequent and troublesome, steel traps were set beside the reptile traps to discourage the raiders or catch them and determine their identity. On several occasions opossums were caught and somewhat less frequently, spotted skunks (Spilogale interrupta) . These skunks probably prey regularly on lizards including the five- hned skink. However no definite records were obtained. Crabb (1941: 356-358) in his food habits study of the spotted skunk in southeastern Iowa, did not record this or any other species of reptile among the items identified in 834 scats. On the Reservation both opossums and skunks were, in many instances, attracted to the reptile traps by the insects and other arthropods in them, rather than by hzards. The striped skunk (Mephitis mephitis) is another of the predators which probably feeds upon the five-lined skink occasionally on this area. In the contents of 103 armadillo stomachs collected in west-central Louisiana, in 1947 and 1948 I found the broken tail of one Eumeces fasciatus. The Hzard itself evidently had escaped ( Fitch, 1949a: 88). Many clutches of lizard eggs were found in the con- tents of the armadillo stomachs and some of these probably were eggs of Eumeces, which are similar to those of other small lizards in the same region (Anolis carolinensis, Sceloporus undtilatus) in size, shape, and color. Among 217 identified prey items from stomachs and scats of Sonoran skinks (Eumeces obsoletus) from northeastern Kansas were remains of three hatchling five-hned skinks. Taylor (1953b: 212) recorded that a Eumeces laticeps shipped from Arkansas to Kan- sas ate an E. fasciatus that was with it in the container. Several authors have recorded predation on Eumeces fasciatus by snakes of various kinds in captivity. Conant (1951: 211) recorded that one was eaten by a blacksnake (Coluber constrictor) placed in the col- lecting sack with it. Anderson (1942: 211 and 216) recorded that a king snake ( Lampropeltis getulus holbrooki ) and a young copper- head (Ancistrodon contortrix) each fed upon them. Hurter (1911: 184) recorded that a milk snake, Lampropeltis trianguhtm syspila, placed in a bucket with a Eumeces fasciatus was found swallowing it a short time later and its tail had been broken off. Ruthven (1911: 268) mentioned that stomachs of milk snakes, L. t. trianguhim, collected in Michigan contained remains of five- lined skinks. Ditmars (1907: 352) wrote that stomachs of several L. t. elapsoides contained Eumeces, and Wright and Bishop ( 1915: 167) wrote of the same kind of king snake in the Okefinokee Swamp Life History and Ecology of Five-lined Skink 137 region: "It feeds on ground lizards, skinks, swifts, and other snakes and lizards." Mr. Richard B. Loomis is of the opinion that the five-lined skink is one of the chief food sources for the milk snake (L. t. syspila). Having kept many of these snakes in captivity and experimentally ofiFered them different types of prey, he found that individuals in- cHned to feed would avidly seize and eat skinks and young mice, but other proffered prey, small adult rodents, snakes, or lizards other than Eumeces were either rejected or were taken with some hesitation. These milk snakes have habitat preferences similar to the skink, which would seem to be one of the most available food sources. Loomis recorded in his field notes that a juvenal blotched king snake (L. calligaster) 310 mm. in total length, taken on April 8, 1950, seven miles southwest of Tulsa, Oklahoma, had eaten a large adult E. jasciatus. Another juvenal blotched king snake that he found under a flat rock near Sunflower, Johnson County, Kansas, regurgitated an adult five-lined skink. Loomis also recorded a juvenal rat snake ( Elaphe guttata emoryi ) and a juvenal pilot black snake (£. obsoleta) each feeding on individuals of Eumeces jasci- atus in captivity. Uhler, Cottam and Clarke (1939: 622) in a study of the contents of the alimentary tracts of 893 snakes of 18 species, from the George Washington National Forest, Virginia, found among the prey items only one skink (species undetermined but most probably E. jasciatus). It had been eaten by one of the two corn snakes {Elaphe guttata) that were examined in the study. On June 11, 1950, in Skink Woods, a young copperhead 335 mm. in snout-vent length and weighing 27.6 grams, had a gravid female skink in its stomach. Another young copperhead (335 mm., 36.1 grams) trapped near Rat Woods on August 28, 1953, had in its stomach a bob-tailed adult five-lined skink. Many copperheads col- lected on the Reservation were kept in captivity for short periods, and from them a total of 44 scats were obtained, each scat containing the remains of one or more prey animals eaten in the wdld. Of this total, five scats contained remains of Eumeces jasciatus, which was one of the more frequent items, although small mammals collec- tively made up the bulk of the scat contents. Parasites Skinks, like many other lizards, are likely to be infested with para- sites. Little attention was devoted to the endoparasites in the present study, but they were noted from time to time. On several occasions small nematodes and flukes were seen in feces voided by 138 Unr'ersity of Kansas Publs., Mus. Nat. Hist. lizards which were handled. Small white cysts were seen in the body cavities of several that were dissected. Harwood (1932: 65) examined for endoparasites nine E. fasciatus along with many other reptiles and amphibians collected near Houston, Texas. Most of them were infested and five kinds of helminths were identified. Two of the skinks were infested with Oswaldocruzia pipiens, a spirurid nematode that was also present in various other lizards, snakes, toads and frogs from the same region; four had Comocercoides dukae, an oxyurid nematode also present in various lizards, snakes, turtles, and frogs; one had in its intestine Oochoristica ettmecis, named as a new species by Har- wood, and found only in Eumeces; one contained Cijsticercus sp. in its body cavity, present in great abundance as white globular structures .6 mm. in diameter (Harwood states that possibly these were larvae of Oochoristica). One skink contained Mesocoelium americanum, a dicrocoelid trematode which was found also in the brown skink {Scincella laterale) and DeKay's snake {Storeria dekayi ) . The ectoparasites of these skinks consist mainly of chiggers. Wharton (1952: 135) lists three species; TromhicuJa alfreddugesi, T. splendens, and T. gurneyi. The first species is the common pest chigger of humans and domestic animals in the United States, and south through tropical America. Wharton lists 136 known hosts which are fairly evenly divided among mammals, birds and reptiles; he lists four kinds of frogs and toads. Trombictda splendens is a similar and closely related species which has been recorded from thirty-eight vertebrate hosts including mammals, birds, reptiles, and a tree-toad. Trombicula gurneyi belongs to a separate subgenus and it was originally recorded from Eumeces fasciatus which seems to be one of the principal hosts. Two of these mites, T. alfreddugesi and T. gurneyi, were on skinks collected on the Reservation, and nearby areas. A four year study of the chiggers in this general region by Loomis (MS), Wolfenbarger (1953) and Kardos (MS) has clarified the ecological relationships of the several kinds of chiggers present, including their local distribution with respect to vegetation, soil type, moisture and temperature, host preferences, and seasonal occurrence. At the quarry, Rat Woods and the pond rock pile, the chigger population consisted chiefly of T. alfreddugesi, while at Skink Woods T. gurneyi was also abundant. In some local situations where they are among the most abundant of vertebrates the skinks probably are important Life History and Ecology of Five-lined Skink 139 as hosts of T. gurneyi. An individual skink may have dozens of chiggers on it at one time but usually there are fewer. There are several favorable sites of attachment. The most favored site is in the axilla. There the scales are minute and granular with exposed areas of thin and tender skin, and the chiggers are well protected from dessication and are not likely to be rubbed off as the skink moves about. Other favorite sites of attachment are: about the insertion of the hind limb, about the cloacal opening, on the eyelids and on the toes. Only occasionally are chiggers found attached on the dorsal surface. When attached in protected spots in the tender skin of the axilla or groin, they are often in dense clusters of a dozen or more. Damage to the skin resulting from the attachment of the first chiggers renders conditions more favorable for the attachment of others. At Rat Ledge and at the quarry, many of the larger Sonoran skinks ( Eumeces ohsoletus ) were cap- tured, and individuals were far more heavily infested than were E. fasciatus from the same places. A single Sonoran skink might be found to have hundreds of chiggers, widely distributed over its body with concentrations at the axillae, groins, lateral neck region, and any injured spots where the protective armor of scales was broken. The reasons for the greater susceptibility of E. ohsoletus are not entirely clear. It is a larger, less active species with coarser scala- tion, and is more subterranean in its habits. The chiggers that attach to skinks seem to occasion but httle dis- comfort. There is no local swelling and inflammation such as occurs in humans. The infestations observed in five-lined skinks were not sufiBciently severe to cause debilitation or any noticeable symptoms. There is, however, a possibility that chiggers are vectors of micro- organisms causing diseases in reptiles, just as they are for certain mammals ( including humans ) in some parts of the world. Bishopp and Trembley (1935:42) record a single kind of tick, Ixodes ricinus scapularis Say, the black-legged tick, as parasitic in its immature stages on Eumeces fasciatus. This tick, however, has been recorded principally from mammals, of which many kinds serve as hosts for its larval, nymphal, and adult stages. Population Composition Population structure obviously differs from place to place and from time to time. Because of the differences in secretiveness and elusiveness between young and adults and between males and fe- males, true sex ratios and age ratios are obscured. In the period of 140 University of Kansas Publs., Mus. Nat. Hist. weeks between the emergence from hibernation and the onset of the breeding season, these skinks tend to be less secretive than at other times, and secondary sexual and age differences in behavior are minimized. A sample at this season should be more represen- tative of the true population composition than samples taken at other times of )ear. In a sample of 308 skinks available for the month of April, including the collections made on the Reservation and on nearby areas, in 1949, 1950, 1951, and 1952, 36.7 per cent were adult males, 28.3 per cent were adult females, and 35.0 per cent were young. That these figures cannot, however, be accepted as an accurate indication of the population composition is shown by the data from the areas where intensive population studies were made. Data are most complete from Skink Woods. For 292 adults taken there over a four year period, the sex ratio was 100:122.6. On this area after the first year of study a substantial proportion of the individuals recorded were repeaters from one year to the next, and in some cases for three or even four successive years. Many could be definitely assigned to a known age group. By analogy the majority of otliers could be tentatively assigned with some as- surance on the basis of measurements, and relatively few were of indeterminate status. By assigning each of these indeterminate in- dividuals to one or another age group, on the basis of greatest prob- ability, the approximate composition of the population could be determined. Of 611 adults, 55 per cent were "two-year olds" (in the season between their second and third hibernations, which was their first breeding season). The percentage was not significantly different in the two sexes. On the average, a pair of adults produces somewhat more than nine eggs per year. From the time individuals of a brood start their development in the egg until they are breeding adults two years later, they undergo such drastic reduction in numbers that, on the average, approximately only one per brood survives. Most of the mortality probably occurs early, especially before hatching, also in the inexperienced hatchlings, and in the first hibernation. In spring, after emergence from hibernation, young are generally taken in smaller numbers than are adults. Their relative scarcity is only apparent, owing to greater secretiveness, and greater elusive- ness when found. In spring, newly matured adults (age class about 21 months) may be taken in somewhat larger numbers than young (age class about 9 months). The latter obviously must be more numerous, in a stable population however, as the 21 month age class necessarily has sustained some loss since it was 9 months old. Life History and Ecology of Five-lined Skink 141 Success of the annual brood varies greatly from year to year, depending on the weather and various other factors. In 1949 evi- dently conditions were near optimum; young hatched early and were especially numerous in late summer. In 1950 these young hatched in 1949 made up 40 per cent of the total catch ( excluding hatchhngs) in Skink Woods and were relatively more numerous than young of the corresponding age group in other years. In 1951, these young of the 1949 brood, grown to adults, made up 70 per cent of the breeding populations, as against 36 per cent for the corresponding class in 1950 and 58 per cent for the corresponding class in 1952. Even after attainment of adulthood, any given age group evi- dently is subject to annual reduction amounting to at least half its numbers. Within six or seven years, at the most, the original num- bers would be reduced to an insignificant percentage. At an age of four or five years individuals probably have attained their maxi- mum size, with obscured pattern and changed proportions sugges- tive of advanced age. Occasional individuals possibly attain much greater age, but certainly few live more than five years. Like most small animals, the five-lined skink has a short life expectancy and a rapid population turnover. As compared with mammals of com- parable sizes, the small rodents and insectivores that are this lizard's community associates and are subject to many of the same hazards, the skink is notably successful, with a much longer life expectancy. For these small mammals the life span is seldom as long as a year. Most kinds of small birds likewise have a life expectancy less than that of the five-lined skink, although somewhat greater than that of small mammals. Density The population density changes constantly, following an annual cycle with gradual reduction to its lowest ebb in late June or early July, then rapid increase to a high point a few weeks later when hatching of the single annual brood has been completed. In a normally successful breeding season the population is at least doubled, but reproductive success varies from year to year, as the population responds to weather conditions that are favorable or unfavorable, even where the environment remains fairly stable. In most places, however, local populations continue upward or down- ward trends for periods of years in response to successional changes which cause progressive improvement or deterioration of local habi- tats. Local populations are likely to be more or less isolated from others by areas where the habitat does not exist. Even in an area 142 University of Kansas Publs., Mus. Nat. Hist. of favorable habitat such as a wooded hillside of several acres, the population is not at all evenly distributed, but concentrations occur along rock outcrops, and about decaying logs, or stone piles. In intervening areas lacking such abundant shelter, and less produc- tive of food, the population is sparse, or there may be no permanent residents. In view of these traits, and the difficulty of obtaining a represen- tative sample, no precise measurements of population density can be made. During the time required to secure a sample, the population undergoes change. At the pond rock pile, an area of approximately .05 acre, the skinks were found in remarkably high concentrations, 57 in 1949, 85 in 1950, 37 in 1951, and 51 in 1952. These numbers represent population densities of, respectively, 1120 per acre, 1960 per acre, 746 per acre, and 1000 per acre. No such concentrations were foimd elsewhere, and probably do not occur in natural habitat. The Skink Woods study area of 2/4 acres is typical of favorable habitat in the region of the study, and the numbers taken there are more significant. For 1949 the 74 skinks recorded comprise an incom- plete sample, and the population density of 33 per acre represented is certainly somewhat too low. For other years the following popu- lation densities (exclusive of hatchlings) are indicated: 1950, 92 per acre; 1951, 61 per acre; 1952, 49 per acre. These figures are only approximate, of course, and it is difficult to judge how accurately they reflect the true numbers. Even the most intensive collecting may be insufiicient to obtain every individual on a small area. Within each season there are shifts of range by some individuals, off the study area and corresponding shifts onto it by others, so that the numbers caught in the course of an entire season are somewhat too high. The individuals taken on the study area may regularly range beyond its boundaries to some extent, so that the seeming population density is somewhat too high. Actually this was prob- ably a minor source of error for the Skink Woods study area, as nearly half its perimeter was bordered by an open field uninhabit- able for the skinks, and the remaining perimeter adjoined areas much less favorable than the central portion. Census of the population of the study area by a ratio such as the "Lincoln Index" used in game management studies was scarcely prac- ticable because of the changing seasonal habits distorting the re- corded ratios of the sexes and of age groups somewhat differently at different stages of the season. These changing ratios tend to pro- duce an erroneously high population figure, unless separate compu- tations are made from the data for adult males, adult females, and Life History and Ecology of Five-lined Skink 143 young. Census figures obtained by this method were erratic but seemed to bear out in a general way, the population figures based on total numbers of individuals taken. In favorable habitat where they occur in high populations of 50 to 100 per acre in spring, these lizards must attain a biomass of a pound or more per acre. Biomass in a population probably fluc- tuates but little during the course of the annual cycle, even though the number of individuals changes greatly. The steady elimination of individuals through various mortality factors, is compensated for by rapid growth of the young. Summary Five-lined skinks were studied for four consecutive years in four small areas, totalling approximately ten acres, on the University of Kansas Natural History Reservation, Douglas County, Kansas. The information gained from intensive study on these areas has been supplemented by data from skinks collected elsewhere in north- eastern Kansas, and from an extensive literature pertaining to this species. The genus Eumeces, to which the common five-lined skink be- longs, has more than 50 species, occurring throughout Central America, North America to the latitude of southern Canada, and, in the Old World, across southern Asia and North Africa. Within the genus, the five-Hned skinks, comprising a dozen species, form a natural group of closely related forms. In this "fasciatus group" nine of the species occur in the Orient, Japan and neighboring islands and the adjacent mainland. The remaining three, including E. fasciatus, occur in the eastern United States. Specific diflFerences are to be found in details of pattern, scalation, and size, and, in some instances, they were long unrecognized. E. fasciatus coincides closely in its distribution with the Deciduous Forest Biome of south- eastern North America. An early Tertiary deciduous forest in Alaska and probably in the Bering Strait area, evidently growing in a humid, mild-temperate climate, included genera of plants that are now most characteristic of southeastern North America along with other kinds now characteristic of forest remnants in south- eastern Asia, and still others characteristic of the western United States. The fasciatus group seemingly dispersed from a northern center that may have coincided with the early Tertiary deciduous forest of Alaska. Eumeces laticeps almost coincides in distribution with E. fasciatus, but does not occur quite so far north, and unlike fasciatus it occurs 144 University of Kansas Publs., Mus. Nat. Hist. throughout Florida. Young are similar in appearance but laticeps is a larger, more powerful species, notably arboreal in its habits. E. inexpectatus much more closely resembles fasciatus, and eco- logical divergence is slight. It is characteristic of hot and dry rocky areas in open woods, and is more southern in distribution, although there is extensive overlap with fasciatus and inexpectatus shares nearly all of its range with laticeps. Eumeces fasciatus is most abundant in well-drained, open, rocky situations within its forest habitat. It is scarce or absent in bottom- land forest that is subject to flooding and requires a forest with openings in the leaf canopy so that sunshine patches for basking are available. In northeastern Kansas, at least, woodlands that are browsed by livestock, and have scanty undergrowth, provide better habitat than those that are protected. E. fasciatus is likely to be most abundant in cutover woodland, and may reach greatest num- bers in artificial situations, such as old rock piles, or the vicinity of deserted sawmills. In the north, the species is increasingly con- fined to open situations, while in the south it may inhabit heavily wooded areas. An abundant supply of moisture is a necessity and the species is limited to a climate of high humidity. Dew normally supplies the source of drinking water, without which the skinks rapidly become emaciated and die. Optimum body temperature was determined to be near 34" C, from a series of temperature readings taken both under natural conditions and in confinement under conditions permitting behavioral thermoregulation. By ther- moregulatory behavior, active skinks in the wild tend to maintain their body temperatures near this level over a wide range of environ- mental temperatures. They can tolerate body temperatures only a few degrees higher, but, within a range of several degrees below 34° C, efficiency is little impaired and incentive to make readjust- ment is slight. At progressively lower temperatures skinks become slower and less efficient. They are, however, capable of copulation at temperatures down to 21° C, and of feeding at 16° C. At 10° C. they are slow and clumsy, barely capable of normal locomotion. At temperatures near freezing they are torpid; they can survive temperatures a little below freezing, but cannot survive being frozen solid. More than half the year is spent in hibernation in north- eastern Kansas. Weight loss is slight during hibernation. Normally the skinks emerge from hibernation in early April in northeastern Kansas, several weeks earlier in the southern states and correspondingly later in the northern part of the range. Maximum activity occurs in the period of weeks following emergence, inter- Life History and Ecology of Five-lined Skink 145 rupted from time to time by cold weather which necessitates return to torpidity. After approximately three weeks of activity the adults attain breeding condition. Breeding males acquire a salmon red suffusion of the head region. They become pugnacious and fight on sight. Fighting does not involve territorial defense. In con- finement males may mutilate or kill each other. In their search for females, and fighting, the breeding males are so much more active and conspicuous than they are at other times of year that published descriptions usually refer to males as red-headed, with no cognizance of the fact that this condition exists for only a few weeks in the annual cycle. Old adult males lose the striped pattern and blue color of the tail of the young, and are golden brown, usually a little darker on the sides. Males find females by a combination of sight and scent. Sexual relations are promiscuous, and there is but little courtship behavior. The male pursues the female and grasps in his jaws loose skin at or behind her shoulder region, and maintains this hold during copulation which lasts about five minutes. Within a few days after insemination, usually in early May, females become actively hostile to males. In late May or early June the gravid females become unusually secretive and excavate nest bur- rows in damp soil under flat rocks, or in rotten wood of decaying logs and stumps. The single annual clutch of eggs is laid in June. The average clutch is somewhat more than nine eggs, with larger and older females slightly exceeding younger and smaller females in average productivity. The female remains in the nest burrow with her clutch most of the time, from laying until after hatching. She alters the nest burrow, dampens it in time of drought, keeps the cavity from being filled with loose soil, prevents the eggs from adhering to the sides or floor of the cavity, and she may repulse certain small predators capable of destroying the eggs if they were left undefended. When they are laid, the eggs are approximately 11 X 7/2 mm. and weigh .4 grams or a little less. By hatching time they have enlarged to 15 x 11 mm. and each weighs about a gram. Recorded incubation periods vary from 27 days to 47 days; develop- ment of the embryo is slowed at low temperatures, and eggs experi- mentally kept in a refrigerator at 11° to 12° C. for periods of days hatched later than others of the same clutch that developed under normal conditions, indicating that development was almost halted in the eggs kept at such low temperatures. Eggs are, however, tolerant of a wide range of temperature, and can develop in nearly dry soil, or can survive partial submersion in water for at least two days. Under weather conditions prevailing in 1951, incubation periods of about six weeks were recorded. Incubation may be shortened 10—3559 146 UxR-ERSiTY OF Kansas Publs., Mus. Nat. Hist. by retention of ova in the oviducts in early stages of embryonic development. Hatching may occur from the first week of July to mid-August, but in any one year most clutches hatch within two weeks of each other. Hatching of eggs in a clutch extends over a day or two. The hatchling gradually becoming active inside the egg, slits the leathery shell with its egg tooth, and spends several hours in the early stages of emergence. After resting with head and shoulders protruding, becoming adjusted to the outside enWron- ment and gaining strength, it lunges from the egg. For a day or two after hatching, the young remains in the nest, being slow and feeble, and handicapped in its movements by the protruding belly distended by the yolk mass. The female usually remains in the nest cavity for a day or two after the eggs hatch, showing affinity for tlie young by curling around them protectively. Family ties are broken as soon as the young leave the nest, and they do not return. Hatchlings average a little less than an inch in snout-vent length, and have a sharply defined five-lined pattern on a black ground color, and vivid blue tail. Hatchlings make rapid growth in late summer, and by the time of their retirement into hibernation, the more successful may have doubled in length, and may have increased their original weight, of approximately .3 or .4 grams, more than eight-fold. After emergence from their first hibernation the young continue their rapid growth. When they are a year old, some of them are as large as small adults. However, they can usually be distinguished from adults by tlie more sharply defined pattern. These grown young retain the hatchling pattern but the contrast between stripes and ground color, and between body and tail is not quite so sharp. Especially in those with regenerated tails, the vivid blue of the hatchling's tail has become much dulled. By the time they retire to their second hibernation, the young have mostly grown to small adult size. A small percentage are retarded in their growth and fail to mature. Upon emergence from their second hibernation, the grown young mature sexually and participate in the annual breeding season, in early May, and they may comprise the majority of breed- ing adults. The ratio of new adults to old adults however varies from year to year depending on the varying fortimes of successive annual broods. The new adults overlap older ones in size, but are usually distinguishable on the basis of tlieir coloration, as they retain the striped body pattern (dulled, especially on the head) and witli distinctly blue color on the tail. In skinks that are three years old or more, the dorsal stripes have become obscured and partly blended with the ground color, which becomes progressively paler with advancing age. Metamorphosis is most complete in old Life History and Ecology of Five-lined Skink 147 males, which retain no trace of the stripes or of the blue color on the tail. Old females usually retain the dark lateral area, and the tail is usually bluish gray, with a blue scale remaining here and there if the tail has not been regenerated. Most individuals lose their original tails, however. By the time the young are approximately two months old, about half have had their tails broken, and by the time they are a year old and have grown to small adult size, three-fourths have regenerated tails. Some individuals may have had their tails broken and regenerated many times. Tails regenerate rapidly and most of the growth is made within the first few weeks. The regenerated tail is not so long as the original lost portion. Individuals tend to stay within small areas which are their regular home ranges. These ranges are only a fraction of an acre in extent, but vary considerably in size and shape according to the individual and the situation. Home ranges of approximately 90-foot diameter for adult males and young, and a little more than 30-foot diameter for adult females are indicated. A home range generally centers about some environmental feature providing shelter and food, such as a log, hollow tree, or rock outcrop. Activity tends to be con- centrated in the central part of the home range. An individual may continue to occupy the same home range throughout its life- time, or it may gradually alter its range, shifting by slow stages into a new area. Some individuals seem to "get lost" or voluntarily shift, and settle in a new area which may be hundreds of feet removed from the original range. Shifts are most likely to occur after emergence from hibernation, when the lizard finds its habitat some- what altered. Individuals released in areas strange to them settled down and established new home ranges, either immediately or after brief wandering. The five-lined skink is a predator, occasionally taking small ver- tebrates (lizards and possibly newborn mice) but depending for most of its food on invertebrates. Of these it takes a wide variety. Spiders are the mainstay of the diet, and various salticids and lycosids are the kinds most frequently preyed upon. Phalangids are also eaten. Of insects, orthopterans (including roaches, ceutho- philid and gryllid crickets, grouse locusts, and small grasshoppers) are most important in the food. Larvae of moths and both larvae and adults of beetles are also taken in quantity. Small snails make up an important part of the diet, and the skinks often eat their own sloughed skins. Less frequently taken food items include certain large ants, centipedes, moths, and miscellaneous insects. Rarely the adult skinks may even eat eggs or young of their own species. 148 University of Kansas Publs., Mus. Nat. Hist. Prey is found by sight and scent, and consists of almost any small animals within a certain size range (small enough to be swallowed entire, but large enough to make up a substantial part of a meal) of types which are not too heavily armored, lack noxious defensive secretions, and live on or in the ground or decaying wood. They are ordinarily crushed in the jaws or battered against the ground, and then swallowed entire. Natural enemies of the five-lined skink certainly include the broad- winged hawk and probably other kinds of hawks and also include various predatory mammals such as the opossum, armadillo, skunks, moles and shrews; snakes (the copperhead, milk snake, king snake, corn snake, and probably others), the Sonoran skink and even the closely related but larger Eumeces laticeps. On the Reservation, the short-tailed shrew was certainly the commonest, and probably by far the most important natural enemy. A high proportion of the skinks examined had scars resembling those inflicted by shrews ex- perimentally confined with skinks in captivity. In time of danger escape reactions vary according to the type of enemy and the at- tending circumstances. Frequently an alarmed skink may escape into a hole or crevice, running directly to it from a distance of sev- eral yards. Under other circumstances a skink may burrow into ground litter of dry leaves and other debris, or may even dive and hide underwater. One of the commonest escape reactions is climb- ing tree trunks. It occurs even in gravid females that are slow and clumsy, being weighed down with eggs. Generally the skink stays on the main trunk of the tree, attempting to conceal itself by utiliz- ing the screening vegetation that is available. In the young, espe- cially, the bright blue tail seems to be used as a decoy, for it is car- ried, arched high and waved conspicuously as the lizard moves about. Rapid lashing movements of the conspicuous tail as the animal darts erratically for shelter may serve to confuse a pursuer, at least as to the direction that the skink has taken. This skink is parasitized by various helminths, both cestodes and nematodes, which inhabit the digestive tract and body cavity. Some of these infest many kinds of amphibian and reptilian hosts, but others may be confined to the five-lined skink. Their life cycles, and efiFect upon the host are not well known. Ectoparasites consist principally of chiggers. Three kinds have been recorded on the skinks; Trombicula alfreddugesi, T. splcndcns, and T. gurneyi. The first two are common pest chiggers which attack humans as well as a wide variety of other mammalian, avian and reptilian hosts. T. gurneyi is a less common species found mainly on Eumeces fasciatus and confined to its woodland habitat. Life History and Ecology of Five-lined Skink 149 LITERATURE CITED Allard, H. a. 1909. Notes on some salamanders and lizards of North Georgia. Science, 30:122-124. Anderson, P. 1942. Amphibians and reptiles of Jackson County, Missouri. Bull. Chi- cago Acad. Sci., 6 (no. ll):203-220. Anonymous. 1945. Principal game birds and mammals of Texas. Texas Game Fish and Oyster Commission, Von Boeckman-Jones Co. 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Press, Waco, Te.xas, xii + 257 pp. Brumwell, M. J. 1951. An ecological survey of the Fort Leavenworth Military Reservation. Amer. Midi. Nat., 45:187-231, 6 pis. Burt, C. E. 1928a. The hzards of Kansas. Trans. Acad. Sci. St. Louis, 26:1-81. 1928b. Insect food of Kansas lizards with notes on feeding habits. Journ. Kansas Ent. Soc, 1:50-68. 1937. The lizards of the southeastern United States. Trans. Kansas Acad. Sci., 40:349-366. Cagle, F. R. 1940. Eggs and natural nests of Eumeces fasciatus. Amer. Midi. Nat., 23:227-233, 2 figs. 1942. Turtle populations in southern Illinois. Copeia, 1942:155-162. 1944. Home range, homing behavior, and migration in turtles. Misc. Publ. Mus. Zool., Univ. Michigan, 61:1-34, 2 pis. Carpenter, C. R. 1952. Comparative ecology of the common garter snake (Thamnophis s. sirtalis), the ribbon snake (Thamnophis s. sauritus) and Butler's garter snake (Thamnophis butleri) in mixed populations. Ecol. Monogr., 22:235-258, 11 6gs. Carr, a. F. 1940. A contribution to the herpetology of Florida. Univ. Florida Publ. Biol. Ser., 3:iv + 118 pp. Clausen, R. T. 1938. Notes on Eumeces anthracinus in central New York. Copeia, 1938:3-7, COCKRUM, E. L. 1952. Mammals of Kansas. Univ. Kansas Publ., Mus. of Nat. Hist., 7:303 pp., 73 figs. Conant, R. 1951. The reptiles of Ohio. (Reprinted with supplement) Amer. Midi. Nat,. 20:1-200, 26 pis., 38 maps. Cook, F. A. 1942. Alligators and hzards in Mississippi. Bull. Mississippi State Fish and Game Comm., v + 20 pp. CORRINCTON, J. D. 1929. Herpetology of the Columbia, South Carohna, region. Copeia, 172:58-83. CowLEs, R. B., and Bocert, C. M. 1944. A preliminary study of the thermal requirements of desert reptiles. Bull. Amer. Mus. Nat. Hist., 83:261-296, pis. 19-29, figs. 1-3. Life History and Ecology of Five-lined Skink 151 Crabb, W. D. 1941. Food habits of the prairie spotted skunk in southeastern Iowa. Joum. Mamm., 22:349-364. Deckert, R. F. 1918. A list of reptiles from Jacksonville, Florida. Copeia, 54:30-33. DiTMARS, R. L. 1907. The reptile book. Doubleday, Page and Co., New York, xxxii -f 472 pp., 136 pis. Dunn, E. R. 1920. Some reptiles and amphibians from Virginia, North Carolina, Ten- nessee and Alabama. Proc. Biol. Soc. Washington, 33:129-138. Edgren, R. a., and Stblle, W. T. 1948. Checklist of Chicago area amphibians and reptiles. Nat. Hist. Misc., 26:1-7, Engels, W. L. 1949. The blue-tailed skinks (Eumeces) of two North Carolina coastal islands. Copeia, 1949 ( 4 ) :269-271. Evans, H. E., and Roecker, R. M. 1951. Notes on the herpetology of Ontario, Canada. Herpetologica, 7:69-71. Fitch, H. S. 1940. A field study of growth and behavior in the fence lizard. Univ. California Publ. Zool., 44:151-172. 1949a. Road counts of snakes in western Louisiana. Herpetologica, 5:87- 90. 1949b. Studies of snake populations in central California. Amer. Midi. Nat., 41:513-579. 1951. A simphfied type of funnel trap for reptiles. Herpetologica, 7:77- 80. 1952. The University of Kansas Natural History Reservation. Univ. Kan- sas Mus. Nat. Hist. Misc. Publ., 4:1-38, 4 pis., 3 figs. Force, E. R. 1930. The amphibians and reptiles of Tulsa County, Oklahoma, and vicinity. Copeia, 1930:25-39. Freiburg, R. E. 1951. An ecological study of the narrow-mouthed toad (Microhyla olivacea) in northeastern Kansas. Trans. Kansas Acad. Sci., 54:374- 386. Gloyd, H. K, 1928. The amphibians and reptiles of Franklin County, Kansas. Trans. Kansas Acad. Sci., 31:115-141. 1932. The herpetological fauna of the Pigeon Lake region, Miami County, Kansas. Occ. Pap. Michigan Acad. Sci. Arts and Letters, 15:389- 409. Gonsr, O. B., and Coin, C. J. 1951. Notes on the natural history of the lizard, Eumeces laticeps in northern Florida. Joum. Florida Acad. Sci., 14:29-33. Gom, C. J., and Richmond, N. D. 1938. Notes on a collection of amphibians and reptiles from New Kent County, Virginia. Ann. Carnegie Mus., 27:301-310, 152 UxrvERSiTi' OF Kansas Publs., Mus. Nat. Hist. Goodman, J. D. 1948. A report on the reptiles collected by J. M. Shaffer from the Keokuk Area, 1863-1895. Proc. Iowa Acad. Sci., 55:365-366. Hamilton, W. J., Jr. 1947, Eumeces fasciatus in northern New York. Copeia, 1947:64. 1948. Hibernation site of the lizards Eumeces and Anolis in Louisiana. Copeia, 1948:211. Haktw^g, N. 1931. Apparent ovoviviparity in the Mexican skink, Eumeces lynxe Wieg- mann. Copeia, 1931:61. Harwood, p. D. 1932. The helminths parasitic in the Amphibia and Reptilia of Houston, Texas, and vicinity. Proc. U. S. Nat. Mus., 81, 17:1-71. Hoffman, R. L. 1945. Range extension for Eumeces laticeps Taylor. Proc. Biol. Soc. Washington, 58:131-132. 1953. Interesting herpesian records from Camp Pickett, Virginia. Her- petologica, 8:171-174. HOLLICK, A. 1936. The Tertiary floras of Alaska. U.S.D.I. Professional Papers, 182: 171 pp., 122 pis. HOYLE, W. L. 1937. Notes on faunal collecting in Kansas. Trans. Kansas Acad. Sci., 39:283-293. Hudson, G. E. 1942. The amphibians and reptiles of Nebraska. Nebraska Cons. Bull., 24:iv -f 146 pp., 20 pis., 32 figs. HUBTER, J. H. 1911. Herpetology of Missouri. Trans. Acad. Sci. St. Louis, 20:59-274. JOPSON, H. 1938. Observation of the survival value of the character of the blue tail in Eumeces. Copeia, 1938:90. 1940. Reptiles and amphibians from Georgetown, South Carolina. Herpe- tologica, 2:39-43. Kabdos, E. H. 1952. Biological and systematic studies on the subgenus Neotrombicula (genus Trombicula) in the United States (Acarina, Trombiculidae ) . Unpublished thesis. University of Kansas Library. Klots, a. B. 1930. Notes on Amphibia and Lacertilia collected at Weymouth, N. J. Copeia, 173:107-111. Leonard, A. B., and Goble, C. R. 1952. Mollusca on the University of Kansas Natural History Reservation. Univ. Kansas Sci. Bull., 34:1013-1055, 2 pis. Linsdale, J. M. 1927. Amphibians and reptiles of Doniphan County, Kansas. Copeia, 1927:75-81. LociEB, E. B. 1939. The reptiles of Ontario. Royal Ontario Mus. Handbook, 4:63 pp., 7 pis. Life History and Ecology of Five-lined Skink 153 Lowe, C. H., Jr., and Norris, K. S. 1950. Aggressive behavior in male sidewinders Crotalus cerastes, with a discussion of aggressive behavior and territoriahty in snakes. Nat. Hist. Misc., 66:1-13. I.YNN, W. G. 1936. Reptile records from Stafford County, Virginia. Copeia, 1936:169- 170. Mansxjeti, R. 1948. "Scorpion" of the tree tops. Natural History, 57:213-215 and 240. McCauley, R. H., Jr. 1939. Differences in the young of Eumeces fasciatus and Eumeces laticeps. Copeia, 1939:93-95. McIlhenny, E. a. 1937. Notes on the five-lined skink. Copeia, 1937:232-233. Mills, C. 1948. A check list of the amphibians and reptiles of Canada. Herpe- tologica, 4 (second supplement): 1-15. Neill, W. T. 1948a. The lizards of Georgia. Herpetologica, 4:153-158. 1948b. Hibernation habits of amphibians and reptiles in Richmond County, Georgia. Herpetologica, 4:107-114. 1950. Reptiles and amphibians in urban areas of Georgia. Herpetologica, 6:113-116. Neill, W. T., and Allen, R. 1950. Eumeces fasciatus in Yloridai. Copeia, 1950:156. Netting, M. G. 1939a. The reptiles of Pennsylvania. Biennial Rept. Pennsylvania Fish. Comm., 1936-1938:122-132. 1939b. Reptiles killed on a "Vermin" campaign in Mercer County, West Virginia. Proc. West Virginia Acad. Sci., 13:162-166. Newmann, H. H., and Patterson, J. T. 1909. Field studies of the behavior of the lizard, Sceloporus spinosus fioridanus. Bull. Univ. Texas Sci. Ser., 15:1-24, 13 figs. Nichols, J. T. 1939. Range and homing of individual box turtles. Copeia, 1939:125-127. Noble, G. K., and Bradley, H. T. 1933. The mating behavior of lizards; its bearing on the theory of sexual selection. Ann. New York Acad. Sci., 35:25-100. Noble, G. K., and Kumpf, K. F. 1936. The function of Jacobson's organ in lizards. Joum. Gen. Psych., 48:371-382. Noble, G. K., and Mason, E. R. 1933. Experiments on the brooding habits of the lizards Eumeces and Ophisaurus. Amer. Mus, Nov., 619:1-29. Noble, G. K., and Teale, H. K. 1930. The courtship of some iguanid and teiid lizards. Copeia, 1930: 54-56. Olfver, J. 1951. Ontogenetic changes in osteodermal ornamentation in skinks. Copeia, 1951:127-130. 154 University of Kansas Publs., Mus. Nat. Hist. Ow'EN, V. 1949. New snake records and notes from Morgan County, Missouri. Hcrpetologica, 5:49-50. Parker, M. V. 1942. Notes on the herpetology of Clay and Greene counties, Arkansas. Proc. Arkansas Acad. Sci., 2:15-30. 1948. A contribution to the herpetology of western Tennessee. Joum. Tennessee Acad. Sci., 22:20-30. Patch, C. L. 1934. Eumeces in Canada. Copeia, 1934:50-51. Pope, C. H. 1944. Amphibians and reptiles of the Chicago area. Chicago Nat. Hist. Mus. Press, 275 pp., 12 pis. Reese, R. W. 1949. The occurrence of Eumeces inexpectatus in Kentucky. Nat. Hist. Misc., 39:1-2. Reynolds, A. E. 1943. The normal seasonal reproductive cycle in the male Eumeces fasci- atus together with some observations on the effect of castration and hormone administration. Joum. Morph., 72:331-375, 2 pis. 1947. Sex hormones responses of the hemipenis of Eumeces fasciatus as reflected by organ weight. Proc. Indiana Acad. Sci., 57:191-198. Reynolds, H. C. 1945. Some aspects of the life history and ecology of the opossum in cen- tral Missouri. Joum. Mamm., 26:361-379. RoDGERS, T. L., and Memmler, V. H. 1943. Growth in the western blue-tailed sldnk. Trans. San Diego Soc. Nat. Hist., 10:61-68, 1 fig. Sandidge, L. L. 1953. Food and dens of the opossum (Didelphis virginiana) in north- eastern Kansas. Trans. Kansas Acad. Sci., 56:97-106. Schmidt, K. P. 1933. Notes on the breeding habits of lizards. Zool. Ser. Field Mus. Nat. Hist. 20:71-76. 1946. On the zoogeography of the Holarctic region. Copeia, 1946:144- 152, 1 fig. 1950. The concept of geographic range, with illustrations from amphibians and reptiles. The Texas Journal of Sciences, 1950, No. 3:326-334. Schroeder, R. C. 1951. A range extension for Eumeces laticeps. Hcrpetologica 7:172. Scott, T. G., and Sheldahl, R. B. 1937. Black-banded skink in Iowa. Copeia, 1937:192. Seibert, H. C, and Hagen, C. W., Jr. 1947. Studies on a population of snakes in lUinois. Copeia, 1947:2-22. Simpson, G. G. 1947. Holarctic mammalian faunas and continental relationships during the Cenozoic. Bull. Geol. Soc. Am., 58:613-688, 6 figs. Shelford, V. E. 1945. The relative merits of the life zone and biome concepts. Wilson Bull., 57:248-252, 1 map. Life History and Ecology of Five-lined Skink 155 Smith, H. M. 1946. Handbook of lizards. Comstock Publishing Co., Ithaca, N. Y. xxi + 557 pp., 135 pis., 136 figs., 41 maps. 1950. Handbook of amphibians and reptiles of Kansas. Univ. Kansas Publ, Mus. Nat. Hist., Misc. Publ., 2:1-336 pp., 233 figs. Smith, H. M., and Etheredge, R. 1953. Resurrection of PZesfiodon BeHu Gray ( Reptilia : Squamata: Lacer- tiha) for a Mexican Skink. Herpetologica, 8:153-161. Smith, H. M., and Leonard, A. B. 1934. Distributional records of amphibians and reptiles in Oklahoma. Am. Midi. Nat., 15:190-196. Smith, M. A. 1935. Reptiha and Amphibia. Vol. Il-Sauria in The fauna of British India including Ceylon and Burma. Taylor and Francis, London, xiii + 440 pp., 92 figs. Smith, P. W. 1947. The reptiles and amphibians of western and central Illinois. Bull. Chicago Acad. Sci., 8:21-40. Stebbins, R. C. 1948. Nasal structure in lizards with reference to olfaction and condition- ing of inspired air. Am. Joum. Anat, 83:183-221. Stebbins, R. C, and Robinson, H. B. 1946. Further analysis of a population of the lizard Sceloporus graciosus gracilis. Univ. CaUfomia Publ. Zool., 48:149-168, 7 pis., 2 figs. Stickel, L. F. 1950. Populations and home range relationships of the box turtle, Ter- rapene c. Carolina (Linnaeus). Ecol. Monogr., 20:351-378. Stickel, W. H., and Cope, J. B. 1947. The home ranges and wanderings of snakes. Copeia, 1947:127-136. SWANSON, P. 1939. Herpetological notes from Indiana. Amer, Midi. Nat., 22:684-696. Taylor, E. H. 1932a. Eumeces inexpectatus: a new American lizard of the family Scinci- dae. Univ. Kansas Sci. Bull., 20:251-258, pis. 17-18. 1932b. Eumeces laticeps: a neglected species of skink. Univ. Kansas Sci. Bull, 20:263-272, pis. 19-20. 1935. Arkansas amphibians and reptiles in the Kansas University Museum. Univ. Kansas Sci. Bull., 22:207-218. 1936. A taxonomic study of the cosmopolitan scincoid Hzards of the genus Eumeces with an account of the distribution and relationships of its species. Univ. Kansas Sci. Bull., 23:1-643. 1943. Mexican hzards of the genus Eumeces, with comments on recent literature of the genus. Univ. Kansas Sci. Bull., 29:269-300. TlHEN, J. A. 1937. Additional records of amphibians and reptiles in Kansas counties. Trans. Kansas Acad. Sci., 40:401-409. TiNBERGEN, N. 1948. Social releasers and the experimental method required in their study. Wilson Bull., 60:6-51. 156 Um\'ERSiTY OF Kansas Publs., Mus. Nat. Hist. TnowBRnxJE, A. H. 1937. Ecological observations on amphibians and reptiles collected in southeastern Oklahoma. Amer. Midi. Nat., 18:285-303. Uhler, F. M., Cott.\m, C, and Clarke, T. E. 1939. Food of snakes of the George Washington National Forest, Virginia. Trans. 4th Amer. Wildlife Conf., Amer. Wildlife Inst., Washington, D. C, 1939:605-622. Webb, G. R. 1949. Notes on the coition and feeding of the blue-tailed skink. Copeia, 1949:294. Werler, J. E., and McCallion, J. 1951. Notes on a collection of amphibians and reptiles from Princess Anne County, Virginia. Amer. Midi. Nat., 45:245-252. Wharton, G. W., and Fuller, H. S. 1952. A manual of the chiggers. Memoirs Ent. Soc. Washington, 4:185 pp., 17 figs. WlLLLAMS, J. B. 1903. A further note on the blue-tailed lizard. Ottawa Naturalist, 17:60. Wolfenbarger, K. 1953. Systematic and Biological Studies on North American Chiggers of the genus Trombicula, subgenus Eutrombicula (Acarina, Trombicu- lidae). Ann. Ent. Soc. Amer., 45:645-677. Wright, A. H., and Bishop, S. C. 1915. A biological reconnaissance of the Okefinokee Swamp in Georgia. 11. Snakes. Proc. Acad. Nat. Sci. Philadelphia, 67:139-192. Transmitted March 25, 1954. n 25-3559 I (Continued from inside of front cover) 24. Geographic range of the hooded skunk. Mephitis macroura, with description of a new subspecies from Mexico. By E. Raymond Hall and Walter W. Dalquest. Pp. 575-580, 1 figure in text. January 20, 1950. 25. Pipistrellus cinnamomeus Miller 1902 referred to the Genus Myotis. By E. Raymond Hall and Walter W. Dalquest. Pp. 581-590, 5 figures in text. January 20, 1950. 26. A synopsis of the American bats of the Genus Pipistrellus. By E. Raymond Hall and Walter W. Dalquest. Pp. 591-602, 1 figure in text January 20, 1950. Index. Pp. 605-638. *Vol. 2. (Complete) MammaU of Washington. By Walter W. Dalquest. Pp. 1-444, 140 figures in text. April 9, 1948. ' Vol. 3. *1. The avifauna of Micronesia, its origin, evolution, and distribi4tion. By Rol-i lin H. Baker. Pp. 1-359, 16 figures in text. June 12, 1951. *2. A quantitative study of the nocturnal migration of birds. By George H. Lowery, Jr. Pp. 361-472, 47 figures in text. JUne 29, 1951. 3. Phylogeny of the waxwings and allied birds. By M. Dale Arvey. Pp. 473- 530, 49 figures in text, 13 tables. October 10, 1951. 4. Birds from the state of Veracruz, Mexico. By George H. Lowery, Jr. and Walter W. Dalquest. Pp. 531-649, 7 figures in text, 2 tables. October 10. 1951. Index. Pp. 651-681. *Vol. 4. (Complete) American weasels. By E. Raymond Hall. Pp. 1-466, 41 plfttes, I v.; 31 figures in text. December 27, 1951. Vol. 5. 1. Preliminary survey of a Paleocene faunule from the Angels Peak area. New Mexico. By Robert W. Wilson. Pp. 1-11, 1 figure in text. February 24, 1951. 2. Two new moles (Genus Scalopus) from Mexico and Texas. By Rollin H. Baker. Pp. 17-24. February 28, 1951. 3. Two new pocket gophers from Wyoming and Colorado. By E. Raymond Hall and H. Gordon Montague. Pp. 25-32. February 28, 1951. 4. Mammals obtained by Dr. Curt von Wedel from the barrier beach of Tamaulipas, Mexico. By E. Raymond Hall. Pp. 33-47, 1 figure in text. October 1, 1951. 5. Comments on the taxonomy and geographic distribution of some North Ameri- can rabbits. By E. Raymond Hall and Keith R. Kelson. Pp. 49-58. October 1, 1951. 6. Two new subspecies of Thomomys bottae from New Mexico and Colorado. By Keith R. Kelson. Pp. 59-71, 1 figiure in text. October 1, 1951. 7. A new subspecies of Microtus montanus from Montana and comments on Microtus canicaudus Miller. By E. Raymond Hall and Keith R. Kelson. Pp. 73-79. October 1. 1951. 8. A new pocket gopher (Genus Thomomys) from eastern Colorado. By E. \ Raymond HaU. Pp. 81-85. October 1, 1951. 9. Mammals taken along the Alaskan Highway. By RoUin H. Baker. Pp. 87- 117, 1 figure in text. November 28, 1951. *10. A synopsis of the North American Lagomorpha. By E. Raymond Hall.» Pp. I 119-202, 68 figures in text. December 15, 1951. 11. A new pocket mouse (Genus Perognathus) from Kansas. By E. Lendell Cockrum. Pp. 203-206. December 15, 1951. 12. Mammals from Tamatdipas, Mexico. By RoUin H.' Baker. Pp. 207-218. December 15, 1951. 13. A new pocket gopher (Genus Thomomys) from Wyoming and Colorado. By E. Raymond Hall. Pp. 219-222. December 15, 1951. 14. A new name for the Mexican red bat. By E. Raymond Hall. Pp. 223-226. December 15. 1951. 15. Taxonomic notes on Mexican bats of the Genus Rhogeessa. By E. Raymond Hall. Pp. 227-232. April 10, 1952. 16. Comments on the taxonomy and geographic distribution of some North Ameri- can woodrats (Genus Neotoma). By Keith R. Kelson. Pp. 233-242. April 10, 1952. 17. The subspecies of the Mexican red-beUied squirrel, Sciurus aureogaster. By Keith R. Kelson. Pp. 243-250, 1 figure in text. April 10, 1952. 18. Geographic range of Peromyscus melanophrys, with description of new sub- species. By Rollin H. Baker. Pp. 251-258, 1 figure in text. May 10, 1952. 19. A new chipmunk (Genus Eutamias) from the Black Hills. By John A. White. Pp. 259-262. April 10, 1952. 20. A new pinon mouse (Peromyscus truei) from Durango, Mexico. By Robert B. Finley, Jr. Pp. 263-267. May 23, 1952. ( Continued on back of cover ) (Continued from inside of back cover) 21. An annotated checklist of Nebraskan bats. By Olin L. Webb and J. Knox Jones, Jr. Pp. 269-279. May 31, 1952. 22. Geographic variation in red-backed mice (Genus Clethrionomvs ) of the south- ern Rocky Mountain region. By E. Lendell Cockrum and Kenneth L. Fitch. Pp. 281-292, 1 figure in text. November 15, 1952. 23. Comments on the taxonomy and geographic distribution of North American microtines. By E. Raymond Hall and E. Lendell Cockriun. Pp. 293-312. November 17. 1952. 24. The subspecific status of tvvo Central American sloths. By E. Raymond Hall and Keith R. Kelson. Pp. 313-337. November 21, 1952. 25. Comments on the taxonomy and geographic distribution of some North Ameri- can marsupials, insectivores, and carnivores. By E. Raymond Hall and Keith R. Kelson. Pp. 319-341. December 5, 1952. 26. Comments on the taxonomy and geographic distribution of some North Ameri- can rodents. By E. Raymond Hall and Keith R. Kelson. Pp. 343-371. December 15. 1952. 27. A synopsis of the North American microtine rodents. By E. Raymond Hall and E. Lendell Cockrum. Pp. 373-498, 149 figures in text. January 15, 1953. 28. The pocket gophers (Genus Thomomys) of CoahuJla, Mexico. By Rollin H. Baker. Pp. 499-514, 1 figure in text. June 1, 1953. 29. Geographic distribution of the pocket mouse, Perognathus fasciatus. By J. Knox Jones, Jr. Pp. 515-526, 7 figures in text. August 1, 1953. 30. A new subspecies of wood rat (Neotoma mexicana) from Colorado. By Robert B. Finley, Jr. Pp. 527-534, 2 figiires in text. August 15, 1953. 31. Four new pocket gophers of the genus Cratogeomys from Jalisco, Mexico. By Robert J. Russell. Pp. 535-542. October 15, 1953. 32. Genera and subgenera of chipmunks. By John A. White. Pp. 543-561, 12 figures in text. December 1, 1953. 33. Taxonomy of the chipmunks, Eutamias quadrivittatus and Eutamias imi- brinus. By John A. White. Pp. 563-582, 6 figures in text. December 1, 1953. 34. Geographic distribution and taxonomy of the chipmunks of Wyoming. By John A. White. Pp. 584-610, 3 figures in text. December 1, 1953. 35. The baculum of the chipmunks of western North America. By John A. White. Pp. 611-631, 19 figures in text. December 1, 1953. 36. Pleistocene Soricidae from San Josecito Cave, Nuevo Leon, Mexico. By James S. Findley. Pp. 633-639. December 1, 1953. 37. Seventeen species of bats recorded from Barro Colorado Island, Panama Canal Zone. By E. Raymond Hall and William B. Jackson. Pp. 641-646. De- cember 1. 1953. Index. Pp. 647-676. *Vol. 6. (Complete) Mammals of Utah, taxonomu and distribution. By Stephen D. Dur- rant. Pp. 1-549, 91 figures in text, 30 tables. August 10, 1952. VoL 7. *1. Mammals of Kansas. By E. Lendell Cockrum. Pp. 1-303, 73 figures in text, 37 tables. August 25, 1952. 2. Ecology of the opossum on a natural area in northeastern Kansas. By Henry S. Fitch and Lewis L. Sandidge. Pp. 305-338, 5 figiues in text. August 24. 1953. 3. The silky pocket mice (Perognathus flavus) of Mexico. By Rollin H. Baker. Pp. 339-347, 1 figure in text. February 15, 1954. 4. North American jumping mice (Genus Zapus). Bv Philip H. Krutzsch. Pp. 349-472, 47 figures in text, 4 tables. April 21, 1954. 5. Mammals from Southeastern Alaska. By Rollin H. Baker and James S. Find- ley. Pp. 473-477. April 21, 1954. 6. Distribution of some Nebraskan Mammals. By J. Knox Jones, Jr. Pp. 479- 487. April 21, 1954. 7. Subspeciation in the montane meadow mouse, Microtus montanus, in Wyoming and Colorado. By Sydney Anderson. Pp. 489-506, 2 figures in text. July 23. 1954. 8. A new subspecies of bat (Myotis velifer) from sovitheastem California and Arizona. By Terry A. Vaughn. Pp. 507-512. July 23. 1954. More numbers will appear in volume 7. Vol. 8. 1. Life history and ecology of the five-lined skink, Eumeces fasciatus. By Henry S. Fitch. Pp. 1-156, 2 pis., 26 figs, in text, 17 tables. September 1, 1954. More numbers will appear in volume 8. University of Kansas Publications Museum of Natural History Volume 8, No. 2, pp. 157-211, figures 1-23, 4 tables — — — ^— ^ November 15, 1954 ■ Myology and Serology of the Avian Family Fringillidae, A Taxonomic Study BY WILLIAM B. STALLCUP I ' i ... lAY 1 8 ia5S r^- / University of Kansas Lawrence 1954 UNIVERSITY OF KANSAS PUBLICATIONS MUSEUM OF NATURAL HISTORY Institutional libraries interested in publications exchange may obtain this series by addressing the Exchange Librarian, University of Kansas Library, Lawrence, Kansas. Copies for individuals, persons working in a particular field of study, may be ootained by addressing instead the Museum ot Natural History, University of Kansas, Lawrence, Kansas. There is no provision for sale of this series Ijy the University Library which meets institutional requests, or by the Museum of Natural History which meets the requests of individuals. However, when individuals request copies from the Museum, 25 cents should be included, for each separate number that is 100 pages or more in length, for the purpose of defraying the costs of wrapping and mailing. * An asterisk designates those numbers of which the Museum's supply (not the Li- brary's supply) is exhausted. Numbers published to date, in this series, are as follows: Vol. 1. 1. The pocket Rophers (Genus Thomomvs) of Utah. By Stephen D. Durrant. Pp. 1-82, 1 figure in text. August 15, 1946. 2. The systematic status of Eunieces pluvial is Cope, and noteworthy records of other amphibians and reptiles from Kansas and Oklahoma. By Hobart M. Smith. Pp. 85-89. August 15, 1946. 3. The tadpoles of Bufo cognntus Say. By Hobart M. Smith. Pp. 93-96. 1 figure in text. August 1.5, 1946. 4. Hybridization between two species of garter snakes. By Hobart M. Smith. Pp. 97-100. August 15, 1946. 5. Selected records of reptiles and amphibians from Kansas. By John Breukel- man and Hobart M. Smith. Pp. 101-112. August 15, 1946. 6. Kyphosis and other variations in soft-shelled tt^es. By Hobart M. Smith. Pp. 117-124, 3 figures in text. July 7. 1947. *7. Natural history of the prairie vole (Mammalian Genus Microtus). By E, W. Jameson, Jr. Pp. 125-151, 4 flgiu-es in text. October 6, 1947. 8. The postnatal development of two broods of great homed owls (Bubo vir- ginianus). By Donald F. Hoffmoister and Henry W. Setzer. Pp. 157-173. 5 figures in text. October 6. 1947. 9. Additions to the list of the birds of Louisiana. By George H. Lowery, Jr. Pp. 177-192. November 7. 1947. 10. A check-list of the birds of Idaho. By M. Dale Arvey. Pp. 193-216. No- vember 29, 1947. 11. Subspeciation in pocket gophers of Kansas. By Bernardo Villa R. and E. Raymond Hall. Pp. 217-236, 2 figures in text. November 29, 1947. 12. A new bat (Genus Mvotis) from Mexico. By Walter W. Dalquest and E. Raymond Hall. Pp. 257-244, 6 figures in text. December 10. 1947. 13. Tadarida femorosacca ( Merriam ) in Tamaulipas, Mexico. By Walter W. Dalquest and E. Raymond Hall. Pp. 245-248, 1 figure in text. December 10, 1947. 14. A new pocket gopher (Thomomvs) and a new spiny pocket mouse (Liomys) from MichoacAn, Mexico. By E. Ravmond Hall and Bernardo Villa R. Pp. 249-256, 6 figures in text. July 26, 1948. 15. A new hylid frog from eastern Mexico. By Edward H. Taylor. Pp. 257- 264, 1 figure in text. August 16, 1948. 16. A new extinct enwdid turtle from the Lower Pliocene of Oklahoma. By Edwin C. Galbreath. Pp. 265-280, 1 plate. August 16, 1948. 17. Pliocene and Pleistocene records of fossil turtles from western Kansas and Oklahoma. By Edwin C. Galbreath. Pp. 281-284. August 16, 1948. 18. A new species of heteromyid rodent from the Middle Oligocene of north- eastern Colorado with remarks on the skull. By Edwin C. Galbreath. Pp. 285-300, 2 plates. August 16, 1948. 19. Speciation in the Brazilian spiny rats (Genus Proechimys, Family Echl- myidae). By Joiio Moojen. Pp. 301-406, 140 figures in text. December 10, 1948. 20. Three new beavers from Utah. Bv Stephen D. Durrant and Harold S. Crane. Pp. 407-417. 7 figiu-es in text. December 24, 1948. 21. Two new meadow mice from Michonc&n, Mexico. By E. Raymond Hall. Pp. 423-427, 6 figures in text. December 24, 1948. 22. An annotated check list of the mammals of Michoac&n, Mexico. By E. Ray- mond Hall and Bernardo Villa R. Pp. 431-472, 2 plates, 1 figure in text. December 27. 1949. 23. Subspeciation in the kangaroo rat, Dipodomys ordii. By Henry W. Setzer. Pp. 473-573, 27 figures in text. 7 tables. December 27. 1949. 24. Geographic range of the hooded skunk. Mephitis macroura, with description of a new subspecies from Mexico. By E. Raymond Hall and Walter W. Dalquest. Pp. 575-580. 1 figure in text. January 20, 1950. (Continued on inilde of back cover) University of Kansas Publications Museum of Natural History Volume 8, No. 2, pp. 157-211, figures 1-23, 4 tables November 15, 1954 Myology and Serology of the Avian Family Fringillidae, A Taxonomic Study BY WILLIAM B. STALLCUP University of Kansas Lav^^rence 1954 University of Kansas Publications, Museum of Natural History Editors: E. Raymond Hall, Chairman, A. Byron Leonard, Robert W. Wilson Volume 8, No. 2, pp. 157-211, 6gures 1-23, 4 tables Published November 15, 1954 University of Kansas Lawrence, Kansas IIAY'rs PRINTED BY FERD VOILAND. JR.. STATE PRINTER TOPEKA. KANSAS 1954 25-4632 Myology and Serology of the Avian Family Fringillidae, a Taxonomic Study BY WILLIAM B. STALLCUP Contents PAGE Introduction 160 Myology of the Pelvic Appendage 162 General Statement 162 Materials and Methods 163 Description of Muscles 164 Discussion of Myological Investigations 175 Comparative Serology 185 General Statement 185 Preparation of Antigens 186 Preparation of Antisera 188 Methods of Serological Testing 188 Experimental Data 190 Discussion of Serological Investigations 190 Conclusions 201 Summary 208 Literature Cited 210 (159) 160 University of Kansas Publs., Mus. Nat. Hist. Introduction The relationships of many groups of birds within the Order Passeriformes are poorly understood. Most ornithologists agree that some of tlie passerine families of current classifications are artificial groups. These artificial groupings are the result of early work which gave chief attention to readily adaptive external struc- tures. The size and shape of the bill, for example, have been over-emphasized in the past as taxonomic characters. It is now recognized that the bill is a highly adaptive structure and that it frequently shows convergence and parallelism. Since studies of external morphology have failed in some cases to provide a clear understanding of the relationships of passerine birds, it seems appropriate that attention be given to other morpho- logical features, to physiological features, and to life history studies in an attempt to find other clues to relationships at the family and subfamily levels. This paper reports the results of. a study of the relationships of some birds of the Family Fringillidae and is based on the com- parative myology of the pelvic appendage and on the comparative serology of saline-soluble proteins. Where necessary for compara- tive purposes, birds from other families have been included in these investigations. It has long been recognized that the Fringillidae include dis- similar groups. Recent work by Beecher (1951b, 1953) on the musculature of the jaw and by TordofiF (1954) primarily on the structure of the bony palate has emphasized the artificial nature of the assemblage although these authors disagree regarding major divisions within it (see below). The Fringillidae have been distinguished from other families of nine-primaried oscines by only one character — a heavy and conical bill (for crushing seeds). Bills of this form have been developed independently in several other, unrelated, groups; as TordofiF (1954:7) has pointed out, Molothrtis of the Family Icteridae, Psittorostra of the Family Drepaniidae, and most members of the Family Ploceidae have bills as heavy and conical as those of the fringillids. The ploceids are distinguished from the fringillids by a single external character: a fairly woll-developcd tenth primary whereas in fringillids the tenth primary is absent or vestigial. TordofF (1954:20) points out, however, that this distinction is of limited value since in other passerine families the tenth primary may be present in some species of a genus and absent in others. The Genus Taxonomic Study, Avian Family Fringillidae 161 Vireo is an example. Furthermore, at least one ploceid ( Philetairus ) has a small, vestigial tenth primary, whereas some fringilhds (Emberizoides, for example) possess a tenth primary w^hich is rather large and ventrally placed (Chapin, 1917:253-254). Thus, it is obvious that studies based on other features are necessary in order to attain a better understanding of the relationships of the birds involved, Sushkin's studies (1924, 1925) of the structure of the bony and horny palates have served as a basis for the division of the FringilH- dae into as many as five subfamilies (Hellmayr, 1938:v): Rich- mondeninae, Geospizinae, Fringillinae, Carduelinae, and Emberi- zinae. Beecher (1951b: 280) points out that "the richmondenine finches arise so uninterruptedly out of the tanagers that ornithologists have had to draw the dividing line between the two groups arbitrarily." His study of pattern of jaw-musculature substantiates this. He states further that the cardueline finches arise without disjunction from the tanagers. He suggests, therefore, that the two groups of "tanager-finches" be made subfamilies of the Thraupidae and that a third subfamily be maintained for the more typical tanagers. He states that the emberizine finches are of different origin, arising from the wood warblers (1953:307). Beecher (1951a: 431; 1953:309) includes the Dickcissel, Spiza americana, in the Family Icteridae, chiefly on the basis of jaw muscle-pattern and the horny palate. Tordoff (1954:10-11) presents evidence that the occurrence of palato-maxillary bones in nine-primaried birds indicates relationship among tlie forms possessing them. He points out that all fringillids except the Carduelinae possess palato-maxillaries that are either free or more or less fused to the prepalatine bar. He points out also that in all carduelines, the prepalatine bar is flared at its juncture with the premaxilla, and that the mediopalatine processes are fused across the midline; noncardueline fringillids lack these character- istics. In addition to the above he cites differences between the carduelines and the "other" fringillids in the appendicular skeletons, in geographic distribution, in patterns of migration, and in habits. Tordoff concludes, therefore, that the carduelines are not fringillids but ploceids, their closest affinities being with the ploceid Subfamily Estrildinae. On the basis of palatal structure, the Fringillinae and Geospizinae are combined with the Emberizinae, the name Fringil- Hnae being maintained for the subfamily. The tanagers merge with the Richmondeninae on the one hand and with the Fringillinae on the other. On this basis, Tordoff ( 1954:32) suggests that the Family 162 UNi\T:RsrrY of Kansas Publs., Mus. Nat. Hist. Fringillidae be divided into subfamilies as follows: Richmondeni- nae, Thraupinae, and Fringillinae. The carduelines are placed as the Subfamily Carduelinae in the Family Ploceidae. From the foregoing, it is apparent that the two most recent lines of research have given rise to conflicting theories regarding relation- ships within the Family Fringillidae. The purpose of my investiga- tion, therefore, has been to gather information, from other fields, which might clarify the relationships of these birds. Since the muscle pattern of the leg in the Order Passeriformes is thought to be one of long standing and slow change, any variation which consistently distinguishes one group of species from another could be significant. With the hope that such variation might be found, a study of the comparative myology of the legs was under- taken. The usefulness of comparative serology as a means of determining relationship has been demonstrated in many investigations. Its use in this instance was undertaken for several reasons: comparative serology has its basis in biochemical systems which seem to evolve slowly; its methods are objective; and its use has, heretofore, re- sulted in the accumulation of data which seem compatible, in most instances, with data obtained from other sources. I acknowledge with pleasure the guidance received in this study from Prof. Harrison B. Tordoff of the University of Kansas. I am indebted also to Prof, Charles A. Leone without whose direction and assistance the serological investigations would not have been possible; to Professors E. Raymond Hall and A. Byron Leonard whose suggestions and criticisms have been most helpful in the preparation of this paper; and to T. D. Burleigh of the U, S, Fish and Wildlife Service for gifts of several specimens used in this work. Assistance with certain parts of the study were received from a con- tract (NR163014) between the Office of Naval Research of the United States Navy and the University of Kansas. Myology of the Pelvic Appendage General Statement In an excellent paper in which the muscles of the pelvic append- age of birds are carefully and accurately described, Hudson (1937) reviewed briefly the more important literature pertaining to the musculature of the leg which had been published to that date. A review of such information here, therefore, seems unnecessary. Myological formulae suggested by Garrod (1873, 1874) have Taxonomic Study, Avian Family Fringillidae 163 been extensively used by taxonomists as aids in characterizing the orders of birds. Relatively few investigations, hov^ever, involving the comparative myology of the leg have been undertaken at family and subfamily levels. The works of Fisher ( 1946 ) , Hudson ( 1948 ) , and Berger (1952) are notable exceptions. The terminology for the muscles used in this paper follows that of Hudson (1937), except that I have followed Berger (1952) in Latinizing all names. Homologies are not given since these are reviewed by Hudson. Osteological terms are from Howard ( 1929 ) . Materials and Methods Specimens were preserved in a solution of one part formalin to eight parts of water. Thorough injection of all tissues was necessary for satisfactory pres- ervation. Most of the down and contour feathers were removed to allow the preservative to reach the skin. In preparing specimens for study, the legs and pelvic girdle were removed and washed in running water for several hours to remove much of the formalin. They were then transferred to a mixture of 50 per cent alcohol and a small amount of glycerine. All specimens were dissected with the aid of a low power binocular micro- scope. Where possible, several specimens of each species were examined for individual differences. Such differences were found to be slight, involving mainly size and shape of the muscles. The size is dependent partly on the age of the bird, muscles from older birds being larger and better developed. The shape of a muscle (whether long and slender or short and thick) is due in part to the position in which the leg was preserved; that is to say, a muscle may be extended in one bird and contracted in another. For these reasons, descriptions and comparisons are based mainly on the origin and insertion of a muscle and on its position in relation to adjoining muscles. Birds dissected in this study are listed below (in the order of the A. O. U. Check-List): SPECIES Vireo olivaceus (Linnaeus) Seiurus motacilla (Vieillot) Passer domesticus ( Linnaeus ) Estrilda amandava (Linnaeus) Poephila guttata ( Reichenbach ) Icterus galbula ( Linnaeus ) Molothrus ater (Boddaert) Piranga rubra (Linnaeus) Richmondena cardinalis ( Linnaeus ) Guiraca caerulea ( Linnaeus ) Passerina cyanea ( Linnaeus ) Spiza americana (Gmelin) Hesperiphona vespertina (Cooper) Carpodacus purpureus (Gmelin) Pinicola enucleator (Linnaeus) Leucosticte tephrocotis (Swainson) Spinus tristis (Linnaeus) Loxia curvirostra Linnaeus Chlorura chlorura (Audubon) Pipilo erijthrophthalmus (Linnaeus) Calamospiza melanocorys Stejneger Chondestes grammacus (Say) Junco hyemalis ( Linnaeus ) Spizella arhorea (Wilson) Zonotrichia querula (Nuttall) Passerella iliaca (Merrem) Calcarius lapponicus (Linnaeus) 164 University of Kansas Publs., Mus. Nat. Hist. Description of Muscles The descriptions which follow are those of the muscles in the leg of the Red-eyed Towhee, Pipilo erythrophthalmus. Differences between species, where present, are noted for each muscle. The term thigh is used-to refer to the proximal segment of the leg; the term cms is used for that segment of the leg immediately distal to the thigh. Muscttlus ilintrochantericus posticus ( Fig. 2 ) . — The origin of this muscle is fleshy from the entire concave lateral surface of the ilium anterior to the ace- tabulum. The fibers converge posteriorly, and the muscle inserts by a short, broad tendon on the lateral surface of the femur immediately distal to the trochanter. It is the largest muscle which passes from the ilium to the femur. Action. — Moves femur forward and rotates it anteriorly. Comparison. — No significant differences noted among the species studied. Musculus iliotrochantericus anticus (Fig. 3). — Covered laterally by the m. iliotrochantericus posticus, this slender muscle has a fleshy origin from the anteroventral edge of the ilium between the origins of the m. sartorius anteriorly and the m. iliotrochantericus medius posteriorly. The m. iliotrochantericus anticus is directed caudoventrally and inserts by a broad, flat tendon on the anterolateral surface of the femur between the heads of the m. femorotibialis externus and m. femorotibialis medius and just distal to the insertion of the m. iliotrochantericus medius. Action. — Moves femur forward and rotates it anteriorly. Comparison. — No significant differences noted among the species studied. Musculus iliotrochantericus medius (Fig. 3). — Smallest of the three iliotro- chantericus muscles, this bandlike muscle has a fleshy origin from the ventral edge of the ihum just posterior to the origin of the m. iliotrochantericus anticus. The fibers are directed caudoventrally, and the insertion is tendinous on the anterolateral surface of the femur between the insertion of the other two ilio- trochantericus muscles. Action. — Moves femur forward and rotates it anteriorly. Comparison. — No significant differences noted among the species studied. Musculus iliacus (Figs. 4, 5). — Arising from a fleshy origin on the ventral edge of the ilium just posterior to the origin of the m. iliotrochantericus medius, this small slender muscle passes posteroventrally to its fleshy insertion on the posteromedial surface of the femur just proximal to the origin of the m. femoro- tibialis internus. Action. — Moves femur forward and rotates it posteriori}'. Comparison. — No significant differences among the species studied. Musculus sartorius (Figs. 1, 4). — A long, straphke muscle, the sartorius forms the anterior edge of the thigh. The origin is fleshy, half from the anterior edge of the ilium and from the median dorsal ridge of this bone and half from the posterior one or two free dorsal vertebrae. The insertion is fleshy along a narrow line on the anteromedial edge of the head of the tibia and on the medial region of the patellar tendon. Action. — Moves thigh forward and upward and extends shank. Comparison. — In Loxia and Spinus, only one-third of the origin is from the last free dorsal vertebra. In Hesperiphona, Carpodacus, Pinicola, and Leuco- sticte, only one-fifth of the origin is from this vertebra. Taxonomic Study, Avian Family Fringillidae 165 Musculus iliotibialis (Fig. 1). — Broad and triangular, this muscle covers most of the deeper muscles of the lateral aspect of the thigh. The middle region is fused with the underlying femorotibialis muscles. In the distal half of this muscle there are three distinct parts; the anterior and posterior edges are fleshy and the central part is aponeurotic. The origin is from a narrow line along the iliac crests — from the origin of the m. sartorius, anteriorly, to the origin of the m. semitendinosus posteriorly. The origin is aponeurotic in the preacetabular region but fleshy in the postacetabular region. The distal part of the muscle is aponeurotic and joins with the femorotibialis muscles in the formation of the patellar tendon. This tendon incloses the patella and inserts on a line along the proximal edges of the cnemial crests of the tibiotarsus. Action. — Extends cms. Comparison. — In Vireo the central aponeurotic portion of this muscle is absent. Musculus femorotibialis externus ( Fig. 2 ) . — Covering the lateral and antero- lateral surfaces of the femur, this large muscle has a fleshy origin from the lateral edge of the proximal three-fourths of the femur. The origin separates the insertion of the m. iliotrochantericus anticus from that of the m. ischio- femoralis and, in turn, is separated from the origin of the m. femorotibialis medius by the insertions of the m. iliotrochantericus anticus and m. iliotro- chantericus medius. Approximately midway of the length of the femur this muscle fuses anteromesially with the m. femorotibialis medius. Distally, the m. femorotibialis externus contributes to the formation of the patellar tendon which inserts on a hne along the proximal edges of the cnemial crests of the tibiotarsus. Action. — Extends cms. Comparison. — No significant diflFerences noted among the species studied. Musculus femorotibialis medius (Figs. 2, 4). — The origin of this muscle, which lies along the anterior edge of the femur, is fleshy from the entire length of the femur proximal to the level of attachment of the proximal arm of the biceps loop. Laterally tliis muscle is completely fused for most of its length with the m. femorotibialis externus and contributes to the formation of the patellar tendon, which inserts on a line along the proximal edges of tlie cnemial crests of the tibiotarsus. Many of the fibers, nevertheless, insert on the proximal edge of the patella. Action. — Extends crus. Comparison. — No significant differences noted among the species studied. Musculus femorotibialis internus (Fig. 4). — One of the most superficial muscles lying on the medial surface of the thigh, this muscle is divided, especially near the distal end, into two parts, lateral and medial. The origin of the lateral part is fleshy from a line on the medial surface of the femur; the origin begins proximally at a point near the insertion of the m. iliacus. The medial, bulkier part of the muscle has a fleshy origin on the medial surface of the lower one-third of the femur. The two parts fuse to some extent above the points of insertion and insert on the medial edge of the head of the tibia. Action. — Rotates tibia anteriorly. Comparison. — Two parts of this muscle variously fused; otherwise, no sig- nificant differences in the species studied. Musculus piriformis ( Fig. 3 ) . — This muscle is represented by the pars caudi- 166 Untv'ersity of Kansas Publs., Mus. Nat. Hist. femoralis only, the pars iliofemoraUs being absent in passerine birds as far as is known. The pars catidi femoralis is flat, somewhat spindle-shaped, and passes anteroventrally from the pygostyle to the femur. The origin is tendinous from the anteroventral edge of the pygostyle, and the insertion is semitendinous on the posterolateral surface of the shaft of the femur about one-fourth its length from the proximal end. Action. — Moves femur posteriorly and rotates it in this direction; moves tail laterally and depresses it. Comparison. — No significant differences noted among the species studied. Musciilus scmitendinostts (Figs. 2, 3, 5). — The origin from the extreme pos- terior edge of the posterior iliac crest of the ilium is fleshy and is aponeurotic from the last vertebra of the synsacrum and the transverse processes of several caudal vertebrae. The straplike belly passes along the posterolateral margin of the thigh. Immediately posterior to the knee, the muscle is divided trans- versely by a ligament. That portion passing anteriorly from the ligament is the m. accessorius semitendinosi (here considered a part of the m. semitendino- sus) and is discussed below. The ligament continues distally in two parts; one part inserts on the medial surface of the pars media of the m. gastrocnemius and the other part fuses with the tendon of insertion of the m. semimembrano- sus. The m. accessorius semitendinosi extends anteriorly from the above men- tioned ligament to a fleshy insertion on the posterolateral surface of the femur immediately proximal to the condyles. Action. — Moves femur posteriorly, flexes the cms and aids in extending the tarsometatarsus. Comparison. — No significant differences noted among the species studied. Muscuhis semimembranosus (Figs. 3, 4, 5). — This straplike muscle passes along the posteromedial surface of the thigh. The origin is semitendinous along a line on the ischium, from a point dorsal to the middle of the ischiopubic fenestra to the posterior end of the ischium, and from a small area of the abdominal musculature posterior to the ischium. The insertion is by means of a broad, thin tendon on a ridge on the medial surface of the tibia immediately distal to the head of this bone. The tendon of insertion passes between the head of the pars media and pars interna of the m. gastrocnemius and is fused with the tendon of the m. semitendinosus. Action. — Flexes crus. Comparison. — No significant differences noted among the species studied. Musculus biceps femoris (Fig. 2). — Long, thin, and somewhat triangular, this muscle lies on the lateral side of the thigh just underneath the m. iliotihialis. Its origin is from a line along the anterior and posterior iliac crests underneath the origin of the m. iliotihialis. Anterior to the acetabulum the origin is aponeu- rotic, and the edge of this aponeurosis passes over the proximal end of the femur. The origin posterior to the acetabulum is fleshy. The most anterior point of origin is difficult to ascertain but it lies near the center of the anterior iliac crest. The most posterior point of origin is immediately dorsal to the posterior end of the ilioischiatic fenestra. Behind the knee the fibers of this muscle converge to form the strong tendon of insertion which passes through the biceps loop, under the tendon of origin of the m. flexor perforatus digiti II, Taxonomic Study, Avian Family Fringillidae 167 and inserts on a small tubercle on the posterolateral edge of the fibula at the point of the tibia-fibula fusion. The biceps loop is tendinous and the distal end attaches to a protuberance on the posterolateral edge of the femur at the proximal edge of the external condyle. The proximal end attaches to the anterolateral edge of the femur im- mediately proximal to the distal end of the loop, which extends posterior to the femur. The distal ami of this loop is connected with the tendon of origin of the m. flexor perforatus digiti II by a strong tendon. Action. — Flexes cms. Comparison. — No significant diflFerences noted among the species studied. Musculus ischiofemoralis (Fig. 3). — Short and thick, this muscle arises di- rectly from the lateral surface of the ischium between the posterior ihac crest and the ischiopubic fenestra. The area of origin extends to the posterior edge of tlie ischium. The insertion is tendinous on the lateral surface of the tro- chanter opposite the insertion of the m. iliotrochantericiis medius. Action. — Moves femur posteriorly and rotates it in this direction. Comparison. — No significant differences noted among the species studied. Musculus obturator internus (Figs. 4, 7). — Lying on the inside of the pelvis and covering the medial surface of the ischiopubic fenestra, is this flat, pinnate, leaf-shaped muscle. The origin is fleshy and is from the ischium and pubis around the edges of this fenestra; none of the fibers arises from the membrane stretched across the fenestra. Anteriorly the fibers converge and fomi a strong tendon that passes through the obturator foramen and inserts on the postero- lateral surface of the trochanter of the femur. Action. — Rotates femur posteriorly. Comparison. — No significant differences noted among the species studied. Muscidus obturator externus ( Fig. 7 ) . — Short and fleshy, this muscle consists of two parts which are not easily separable but which may be traced through- out its length. The parts are more nearly distinct at the origin. The dorsal part arises directly from the ischium along the dorsal edge of the obturator foramen. The larger ventral part arises directly from the anterior and ventral edges of the obturator foramen. The fibers of the dorsal part pass anteriorly, cover the tendon of the m. obturator internus laterally, and insert on the tro- chanter around the point of insertion of the latter muscle. The fibers of the ventral part pass parallel with the tendon of the m. obturator internus and insert on the trochanter immediately distal and posterior to the tendon of the latter muscle. Action. — Rotates femur posteriorly. Comparison. — In Passer, Estrilda, Poephila, Hesperiphona, Carpodacus, Pini- cola, Leucosticte, Spinus and Loxia, this muscle is undivided and, in its posi- tion, origin, and insertion, resembles the ventral part of the bipartite muscle described above. The origin is from the anterior and ventral edges of the obturator foramen and the insertion is on the trochanter of the femur immedi- ately distal and posterior to the insertion of the m. obturator internus. In all other genera examined, the muscle is bipartite. In Chlorura the dorsal part is larger and better developed than it is in the other genera. Musculus adductor longus et brevis (Figs. 3, 4, 5). — Consisting of two dis- tinct, straplike parts, this large muscle lies on the medial surface of the thigh, posterior to the femur. 168 University of Kansas Publs., Mus. Nat. Hist. The pars anticus has a semitendinous origin on a line that extends posteriorly from the posteroventral edge of the obturator foramen to a point half way across the membrane that covers the ischiopubic fenestra. The insertion is fleshy along the posterior surface of the femur from the level of the insertion of the m. piriformis distally to the medial surface of the internal condyle. Tlie pars posticus originates by a broad, flat tendon on a line across the posterior half of the membrane that covers the ischiopubic fenestra. The in- sertion is at the point of origin of the pars media of the m. gastrocnemius on the posteromedial surface of the proximal end of the internal condyle of the femur. There is a broad tendinous connection with the proximal end of the pars media of the m. gastrocnemius. The anterior edge of the pars posticus is overlapped medially by the posterior edge of the pars anticus. Action. — Flexes thigh; may flex crus also and may extend tarsometatarsus. Comparison. — In Vireo olivaceous, the origin of this muscle does not extend the length of the ischiopubic fenestra. The origin, furthermore, is along the dorsal edge of the ischiopubic fenestra and not from the membrane covering the fenestra. Finally, in this species, the origin of the pars posticus is fleshy. Musculus tibialis anticus ( Figs. 2, 5 ) . — Lying along the anterior edge of the crus, a part of this muscle is covered by the m. peroneus longus. The origin is by two distinct heads, each of which is pinnate. The anterior head arises directly from the edges of the outer and inner cnemial crests. The posterior head arises by a short, strong tendon from a small pit on the anterodistal edge of the external condyle of the femur. This tendon and the proximal end of the muscle pass between the head of the fibula and the outer cnemial crest. The two heads of the muscle fuse at a place slightly more than one-half of the distance down the crus. At the distal end of the cms this muscle gives rise to a strong tendon which passes under a fibrous loop immediately proximal to the external condyle in company with the m. extensor digitorum longus and which passes between the condyles of the tibia and inserts on a tubercle on the anteromedial edge of the proximal end of the tarsometatarsus. Action. — Fle.xes tarsometatarsus. Comparison. — No significant difi^erences noted among the species studied. Musculus extensor digitorum longus (Figs. 3, 5, 8). — Slender and pinnate, this muscle lies along the anteromedial surface of the tibia. The origin is fleshy from most of the region between the cnemial crests and from a hne along the anterior surface of the proximal fourth of the tibia. Approximately two-tliirds of the distance down the crus the muscle gives rise to the tendon of insertion which passes through the fibrous loop near the distal end of the tibia in com- pany with the m. tibialis anticus. The tendon then passes along beneath the supratcndinal bridge at the distal end of the tibia, traverses the anterior inter- condylar fossa, and passes beneath a bony bridge on the anteromedial surface of the proximal end of the tarsometatarsus. The tendon continues along the anterior surface of the tarsometatarsus to a point immediately above the bases of the toes and there gives rise to three branches, one to the anterior surface of each foretoe. The insertions of each branch are on the anterior surfaces of the phalanges as shown in Fig. 8. Action. — Extends foretoes. Comparison. — This muscle is weakly developed in Leucosticte and Calcarius; the belly is slender and extends only half way down the crus before giving rise Taxonomic Study, Avian Family Fringillidae 169 to the tendon of insertion. The functional significance of this variation is dif- ficult to understand. The convergence in muscle pattern shown by these two genera, however, is in all probability the result of similarities in behavior pat- terns. These birds perch less frequently than do the other birds studied. Thus, the toes are neither flexed nor extended as often; the smaller size of the m. extensor digitorum longus may have resulted in part from this lessened activity. Except for the variations just noted, there are no significant differences among the species studied; even the rather complex patterns of insertion are identical. Muscuhis peroneus longus (Fig. 1). — Relatively thin and straplike, this muscle lies on the anterolateral surface of the cms and is intimately attached to the underlying muscles. The part of the origin from the proximal edges of the inner and outer cnemial crests is semitendinous but the part of the origin from the lateral edge of the shaft of the fibula is tendinous. Approximately two-thirds the distance down the cms the muscle gives rise to the tendon of insertion. Immediately above the external condyle of the tibiotarsus this tendon divides. The posterior branch inserts on the proximal end of the lateral edge of the tibial cartilage. The anterior branch passes over the lateral surface of the external condyle to the posterior surface of the tarsometatarsus and there unites with the tendon of the m. flexor pcrforatus digiti III. Action. — Extends tarsometatarsus and flexes third digit. Comparison. — No significant differences noted among the species studied. Muscuhis peroneus brevis (Figs. 2, 3). — Lying along the anterolateral sur- face of the tibia, this slender, pinnate muscle arises from a fleshy origin along this surface and along the anterior surface of the fibula from a point im- mediately proximal to the insertion of the m. biceps femoris to a point approxi- mately two-thirds of the way down the cms. Near the distal end of the tibia the muscle gives rise to the tendon of insertion that passes through a groove on the anterolateral edge of the tibia just above the external condyle. Here the tendon is held in place by a broad fibrous loop and passes under the anterior branch of the tendon of insertion of the m. peroneus longus and inserts on a prominence on the lateral edge of the proximal end of the tarsometatarsus. Action. — Extends tarsometatarsus and may abduct it slightly. Comparison. — No significant differences noted among the species studied. Muscuhis gastrocnemius (Figs. 1, 4). — The largest muscle of the pelvic ap- pendage, it covers superficially all of the posterior surface, most of the medial surface, and half of the lateral surface of the cms. The muscle originates by three distinct heads. The pars externa covers the posterolateral surface of the cms, is intermediate in size between the other two heads, and arises by a short, strong tendon from a small bony protuberance on the posterolateral side of the distal end of the femur immediately proximal to the fibular condyle. The tendon is intimately connected with the distal arm of the loop for the m. biceps femoris. The pars media is the smallest of the three heads and lies on the medial sur- face of the cms. The head of the pars media is separated from the pars interna by the tendon of insertion of the m. semimembranosus and originates by a short, strong tendon from the posteromedial surface of the proximal end of the internal condyle of the femur. The proximal portion of the pars media has tendinous connections with the tendon of the m. semitendinosus and with the pars posticus of the m. adductor longus et brevis. 170 University of Kansas Publs., Mus. Nat. Hist. The pars interna is the largest of the three heads and covers most of the medial surface of the cms. This head in its proximal portion is distinctly divided into anterior and posterior parts, the foniier overlapping the latter medially. The origin of the posterior part is fleshy from the anterior half of the tibial head. Some of the fibers of the anterior part arise directly from the inner cnemial crest while its remaining fibers arise from the patellar tendon ( Fig. 1 ) and form a band that extends around the anterior surface of the knee, covering die insertion of the m. sartorius. Approximately half way down the crus, the three heads give rise to the tendon of insertion, the tendo achillis, which passes over and is tightly bound to the posterior surface of the tibial cartilage. The insertion is tendinous on the posterior surface of the hypotarsus and along the posterolateral ridge of the tarsometatarsus. This tendon seems to be continuous with a fascia which forms a sheath around the posterior surface of the tarsometatarsus holding the other tendons of this region firmly in the posterior sulcus. Action. — Extends tarsometatarsus. Comparison. — Study of the pars externa and pars media reveals no sig- nificant differences among the species dissected. The pars interna, however, is subject to some variation which is described below. Pars interna bipartite Vireo Chlorura Seiurus Pipilo Icterus Calamospiza Molothrus Chondestes Piranga Junco Richmondena Spizella Guiraca Zonotrichia Passerina Passerella Spiza Calcarius The tv/o parts of the m. gastrocnemius are most distinct in Vireo. Icterus, Molothrus, Richmondena, Guiraca, and Passerina lack the fibrous band that passes around the front of the knee. In Spiza this band of fibers is smaller than in the other species. Pars interna undivided Passer Pinicola Estrilda Leucosticte Poephila Spinus Ilesperiphona Loxia Carpodacus In Leucosticte, although the pars interna is undivided, there is a band of fibers which extends around the front of the knee (sec discussion, p. 183). Muscuhis plantaris (Fig. 5). — Small and slender, this muscle lies on the posteromedial surface of the crus, beneath the pars interna of the m. gastro- cnemius and originates by fleshy fibers from the posteromedial surface of the proximal end of the tibia immediately distal to tlic internal articular surface. The belly extends approximately one-sixth of the way down the crus and gives rise to a long, slender tendon that inserts on the proximomedial edge of the tibial cartilage. Taxonomic Study, Avian Family Fringillidae 171 Action. — Extends tarsometatarsus. Comparison. — No significant differences noted among tlie species studied. Mtisculus flexor perforatus digiti II (Figs. 3, 9). — This is a slender muscle whicfi lies on tlie lateral side of the crus beneath the pars externa of the m. gastrocnemius and is intimately connected anteroniedially with the m. flexor digitorum longus and posteromedially with the m. flexor hallucis longus. The origin is by a strong tendon from the lateral surface of the external condyle of the femur at the point of origin of the m. flexor perforans et perforatus digiti II. This tendon serves also as the origin of the anterior head of the m. flexor hallucis longus. The tendon connects also by a broad tendinous band with the distal arm of the loop for the m. biceps femoris and by a similar band with the lateral edge of the fibula imm.ediately distal to the head. The tendon of in- sertion passes distally, perforates the tibial cartilage near its lateral edge, tra- verses the middle medial canal of the hypotarsus (Fig. 6), and passes distally to the foot. At the distal end of the tarsometatarsus the tendon is held against the medial surface of the first metatarsal by a straplike sheath. The tendon then passes over a sesamoid bone between the first metatarsal and the base of the second digit and is bound to this bone by a sheath. The tendon inserts mainly along the posteromedial edge of the proximal end of the first phalanx of the second digit, although the termination is sheathlike and covers the entire posterior surface of this phalanx. This sheathlike termination is perforated by the tendons of the m. flexor perforans et perforatus digiti II and the branch of the m. flexor digitorum longus that inserts on the second digit. Action. — Flexes second digit. Comparison. — In Vireo this muscle is larger and more deeply situated than it is in the other species examined and has no connection with the m. flexor hallucis longus. Mtisculus flexor perforatus digiti III (Fig. 5). — Long and flattened, this muscle lies on the posteromedial side of the crus beneath the m. gastrocnemius. The belly is tightly fused laterally with the belly of the m. flexor hallucis longus and posteriorly with the belly of the m. flexor perforatus digiti IV. The origin is by a long, strong tendon from a small tubercle just medial to, and at the proximal end of, the external condyle of the femur. Below the middle of the crus this muscle terminates in a strong tendon which perforates the tibial cartilage near its lateral edge. In this region the tendon is sheathlike and wrapped around the tendon of the m. flexor perforatus digiti IV. These two tendons together pass through the posterolateral canal of the hypotarsus (Fig. 6). Immediately distal to the hypotarsus the two tendons separate, and the tendon of the m. flexor perforatus digiti III receives a branch of the tendon of the m. peroneus longus. The tendon passes distally over the surface of the second trochlea, and its insertion is sheathlike on the posterior surface of the first phalanx, and on the proximal end of the second. In the area of insertion this tendon is perforated by that of the m. flexor perforans et perforatus digiti III and by that of the m. flexor digitorum longus to the third digit. Action. — Flexes digit III. Comparison. — In Passer, Estrilda, Poephila, Hesperiphona, Carpodacus, Pinicola, Leucosticte, Spinus, and Loxia the edges of the sheathlike tendon are thickened at the points of insertion, so that the tendon appears to have two branches which insert along the posterolateral edges of the first phalanx and are connected medially by a fascia. 172 UNivERsiTi' OF Kansas Publs., Mus. Nat. Hist. Muscuhis flexor perforatus digiti IV (Fig. 3). — Extending along the pos- terior edge of the cms, this slender muscle lies beneath the m. gastrocnemius. The belly is fused with those of the m. flexor hallueis longus and m. flexor per- foratus digiti III. Its origin is fleshy from the intcrcondyloid region of the distal end of the femur and has a few fibers arising from the tendon of origin of the m. flexor perforatus digiti III. Near the distal end of the crus the muscle gives rise to the strong tendon of insertion which perforates the tibial cartilage near its lateral edge and in this region is ensheathed by the tendon of the m. flexor perforatus digiti III. The two tendons pass together through the posterolateral canal of the hypotarsus (Fig. 6). The tendon continues distally along the tarsometatarsus and the posterior surface of digit IV. The tendon bifurcates at approximately the middle of the first phalanx. A short lateral branch in- serts on the posterolateral edge of the proximal end of the second phalanx. The long medial branch is perforated by a branch of the m. flexor digitorum longus; the distal end is flattened, has thickened edges, and inserts over the posterior surfaces of the distal end of the second phalanx, and over the proximal end of the third phalanx. Action. — Flexes digit IV. Comparison. — No significant differences noted among the species studied. Musculus flexor perforans et perforatus digiti II (Figs. 2, 9). — Small and spindle-shaped, this muscle lies on the posterolateral side of the cms immedi- ately beneath the pars externa of the m. gastrocnemius. The origin is fleshy and arises in company with the m. flexor perforans et perforatus digiti III from a point on the posterolateral surface of the distal end of the femur between the point of origin of the pars externa of the m. gastrocnemius and the fibidar condyle. The belly extends approximately one-fourth of the way down the crus and gives rise to the tendon of insertion which passes distally and super- ficially through the posterior edge of the tibial cartilage. The tendon traverses the posteromedial canal of the hypotarsus (Fig. 6) and continues along the posterior surface of the tarsometatarsus. Between the first metatarsal and the base of the second digit the tendon is enclosed by the medial surface of a sesamoid bone. This tendon then perforates that of the m. flexor perforatus digiti II at the level of the first phalanx and in turn is perforated by the tendon of the m. flexor digitorum longus at the proximal end of the second phalanx. The insertion is on the posterior surface of the second phalanx. Action. — Flexes digit II. Comparison. — In Passer, Estrilda, Poephila, Hesperiphona, Carpodacus, Finicola, Leucosticte, Spinus, and Loxia the proximal portion of this muscle is more intimately connected with the posterior edge of the m. flexor perforans et perforatus digiti III than it is in the other species examined. Musculus flexor perforans et perforatus digiti III ( Fig. 2 ) . — Long and pin- nate, this muscle lies on the lateral surface of the cms beneath the m. peroneus longus and pars externa of the m. gastrocnemius. There are two distinct heads. The origin of the anterior head is fleshy from the proximal edge of the outer cnemial crest and from the internal edge of the distal end of the patellar tendon. The posterior head arises by a tendon from the femur in company with the m. flexor perforans et perforatus digiti II, is connected also with the tendon of origin of the m. flexor perforatus digiti II, and is loosely attached to the head of the fibula. Fibers from the belly of the muscle attach throughout its length Taxonomic Study, Avian Family Fringillidae 173 to the lateral edge of the fibula, and the muscle is tightly fused also witli adjacent muscles. The tendon of insertion is formed approximately one-half the way down the crus. The tendon perforates the posterior surface of tlie tibial cartilage and passes through the posteromedial canal of the hypotarsus (Fig. 6). At the base of the third digit the tendon ensheathes that of the m. flexor digitorum longus and the two together perforate the tendon of the m. flexor perforatus digiti III. Immediately distal to this perforation the tendon of the m. flexor perforans et perforatus digiti III ceases to ensheath that of the m. flexor digitorum longus. The latter passes beneath that of the former. Near the distal end of the second phalanx the tendon of the m. flexor digitorum longus perforates that of the m. flexor perforans et perforatus digiti III. The latter inserts on the posterior surface of the distal end of the second phalanx and the proximal end of the third. Action. — Flexes digit III. Comparison. — In Passer, Estrilda, and Poephila, and in all the cardueline finches examined the proximal portion of this muscle is more intimately con- nected with the anterior edge of the m. flexor perforans et perforatus digiti II than it is in the other species examined. Mtisciilus flexor digitorum- longus (Figs. 3, 5). — This strong, pinnate muscle is deeply situated along the posterior surfaces of the tibia and fibula. There are two distinct heads of origin. The lateral head arises by means of fleshy fibers from the posterior edge of the head of the fibula. The medial head arises by means of fleshy fibers from the region under the ledgelike external and in- ternal articular surfaces of the proximal end of the tibia. Neither head has any connection with the femur in contrast to the condition, described by Hudson (1937:46-47) in the crow, Corvus brachyrhynchos, and in the raven, Corvus corax. Near the point of insertion of the m. biceps femoris the two heads fuse. The common belly is attached by fleshy fibers to the posterior surface of the tibia and fibula for two-thirds of the distance down the crus. Near the distal end of the crus the muscle terminates in a strong tendon which passes deeply through the tibial cartilage and traverses the anteromedial canal of tlie hypo- tarsus (Fig. 6). About midway down the tarsometatarsus this tendon becomes ossified. Immediately above the bases of the toes it gives rise to three branches, one to the posterior surface of each of the foretoes. These branches perforate the other flexor muscles of the toes as described in the accounts of those muscles and insert as follows: The branch to digit II inserts on the base of the ungual phalanx and by a stout, tendinous sHp on the distal end of the second phalanx (Fig. 9). The branch to digit III inserts on the base of the distal end of the third phalanx and a stronger slip to the distal end of the second or proximal end of the third. The branch to digit IV inserts on the base of the ungual phalanx, with one tendinous slip to the distal end of the third phalanx and another to the distal end of the fourth. Action. — Flexes foretoes. Comparison. — No significant differences noted among the species studied. Muscuhis flexor hallucis longus (Fig. 3). — Situated immediately posterior to the m. flexor digitorum longus, the belly of this large, pinnate muscle is in- timately connected anteriorly to that of the m. flexor perforatus digiti II. The m. flexor hallucis longus arises by two heads which are separated by the tendon of insertion of the m. biceps femoris. The smaller anterior head arises from 2—4632 174 University of Kansas Publs., Mus. Nat. Hist. the same tendon as does the m. flexor perforatus digiti II. The larger posterior head arises by means of fleshy fibers from the intercondyloid region of the pos- terior surface of the femur along with tlie m. flexor perforatus digiti III and IV. The two heads join just distal to the point of insertion of the m. biceps femoris. There is no trace of a tendinous band connecting the two heads as there is in the crow and in the raven (Hudson, 1937:49). Near the distal end of the shank the muscle gives rise to a strong tendon which perforates the tibial cartilage along its lateral edge and passes through the anterolateral canal of the hypotarsus (Fig. 6). The tendon crosses over to the medial surface of the tarsometatarsus, passes distally, and perforates the sheathlike tendon of the m. flexor hallucis brevis between the first metatarsal and the trochlea for digit II. The tendon continues along the posterior surface of the hallux and has a double insertion; the main tendon attaches to the base of the ungual phalanx and a smaller branch inserts on the distal end of the proximal phalanx. Action. — Flexes hallux. Comparison. — In Vireo this muscle has only the posterior head of origin and is not connected with the m. flexor perforatus digiti II. The muscle is pro- portionately smaller and weaker than in any of the other species studied. Musculus extensor hallucis longus (Fig. 4). — One of the smallest muscles of the leg, the origin is fleshy from the anteromedial edge of the proximal end of the tarsometatarsus. The belly is long and slender and terminates distally in a slender tendon which passes distally along the posterior surfaces of the first metatarsal and the first digit. The insertion is on the base of the ungual phalanx. Near the distal end of the proximal phalanx, the tendon passes be- tween two thick bands of fibro-elastic tissue which insert also on the ungual phalanx. These bands of tissue function as automatic extensors of the claw. Action. — Extends hallux; action must be slight. Comparison. — In Vireo this muscle is proportionately larger and better de- veloped than it is in any of the other species examined. Musculus flexor hallucis brevis (Fig. 4). — This minute muscle has a fleshy origin from the medial surface of the hypotarsus. The short belly terminates in a weak, slender tendon which passes down the posteromedial surface of the tarsometatarsus and into the space between the first metatarsal and the trochlea for digit II. In this region the tendon envelops the tendon of the m. flexor hallucis longus and inserts on the distal end of tlie first metatarsal and on the proximal end of the first phalanx of the first digit. Action. — Flexes hallux; action must be slight. Comparison. — The small size of this muscle makes it exceedingly difficult to study. The muscle is larger in Vireo than in any of the other species examined. This may be correlated with the smaller size of the m. flexor hallucis longus in this species. The muscle docs not seem to be so well developed in the cardue- line finches as it is in the other species. Musculus abductor digiti IV (Fig. 2). — E.\tremely small, delicate and diffi- cult to demonstrate, this muscle arises in a fleshy origin immediately from underneath the posterior edge of the external cotyla of the tarsometatarsus. The tendon of insertion is long and slender and inserts along the lateral edge of the first phalanx of digit IV. Taxonomic Study, Avian Family Fringillidae 175 Action. — Abducts digit IV. Comparison. — No significant differences noted among the species studied. Musculus lumbricalis. — Semitendinous throughout its length, this muscle arises from the ossified tendon of the m. flexor digitorum longus at a point im- mediately proximal to the branching of this tendon. The insertion is on the joint pulleys and capsules at tlie base of the third and fourth digits. Action.— Hudson (1937:57) states that: "iMeckel (vide Gadow— 1891, p. 204 ) considered this muscle as serving to draw the joint pulley behind in order to protect it from pinching during the bending of the toes. It perhaps also tends to flex the third and fourth digits." Comparison. — No significant difi^erences noted among the species studied. Discussion of the Myological Investigations Simpson (1944:12) and others have emphasized that different parts of organisms evolve at different rates. Beecher (1951b:275) in stating that ". . . the hind limb is very similar in muscle pattern throughout the Order Passeriformes and seems to have be- come relatively static after attaining a high level of general eflBciency . . ." implies that the muscle pattern of the leg must be one of long standing and slow change. This concept v^as emphasized by Hudson (1937) who found but little variation in muscle pattern among members of the several families of passerine birds. The con- cept is further confirmed by the present investigation. The intricate patterns of origin and of insertion seem to remain almost the same throughout the order in spite of adaptive radiation which has oc- curred. Two major differences in patterns of leg-musculature, however, were found among the species studied, and these differences are significant since they are consistent between subfamihes. The muscles involved are the m. obturator externus and the pars interna of the m. gastrocnemius. The m. obturator externus is bipartite, consisting of dorsal and ventral parts, in the passerine species studied by Hudson ( 1937 ) and in all of the species examined by me except the ploceids and the cardueline finches. In the ploceids and cardueline finches this muscle is undivided and resembles in its position, origin, and inser- tion only the ventral portion of the muscle found in the other birds studied. It is difficult to imagine what advantage or disadvantage might be associated with the bipartite or with the undivided condi- tion. The action of this muscle is to rotate the femur (right femur clockwise, left femur counterclockwise), and certainly the greater mass of the bipartite muscle could lend greater strength to such action. The possible significance of this is discussed below. 176 Untversity of Kansas Publs., Mus. Nat. Hist. List of Abbreviations Used in Figures Abd. dig. IV M. abductor digiti IV Ace M. accessorius semitendinosi Add. long M. adductor longus et brevis Anterolat. can Anterolateral canal of hypotarsus Anteromed. can Anteromedial canal of hypotarsus Bic, fern M. biceps femoris Bic. loop Loop for m. biceps femoris Ext. cot External cotyla Ext. dig. 1 M. extensor digitorum longus Ext. hal. 1 M. extensor halhicis longus Fern. tib. ext M. femorotibialis externus Fern. tib. int M. femorotibialis internus Fern, tib med M. femorotibialis medius F. dig 1 M. flexor digitorum longus F. hal. brev M. flexor halhicis brevis F. hal. 1 M. flexor hallucis longus F. p. et p. d. II M. flexor perforans et perforatus digiti II F. p. et p. d. Ill M. flexor perforans et perforatus digiti III F. per. d. II M. flexor perforatus digiti II F. per. d. Ill M. flexor perforatus digiti III F. per. d. IV M. flexor perforatus digiti IV Gas M. gastrocnemius Iliacus M. iliacus II. tib M. iliotibialis II. troc. ant M. iliotrochantencus anticus II. troc. med M. iliotrochantericus medius II. troc. post M. iliotrochantericus posticus Int. cot Internal cotyla Isch. fern M. ischiofemoralis Midmed. can Midmedial canal of hj'potarsus Obt. ext M. obturator externus Obt. int M. obturator internus P. ant Pars anticus P. ext Pars externa P. int Pars interna P. med Pars media P. post Pars posticus Per. brev M- peroncus brevis Per. long M. peroncus longus Pirif M. piriformis Plan M. plantaris Posterolat. can Posterolateral canal of hjTiotarsus Posteromcd. can Posteromedial canal of hypotarsus Sar M. sartorius Semim M. semimembranosus Scmit M. scmitcndinosus Tib. ant M- tibialis anticus Tib. cart Tibial cartilage Taxonomic Study, A\tan Family FRiNGiLLroAE 177 Sor tl tib 60s. (p. int) Tib ant Per. long Per brev Tib. cort. Fig. 1. Pipilo erythrophthalmus. Lateral view of the superficial muscles of the left leg, X 1-5- 178 University of Kansas Publs., Mus. Nat. Hist. II. f r c post II f roc n t Fem. tl b. me d Fern ti b ex f Tib ont. Per. brev Pirif Bic fem Se m im Se m I f Ace Bic loop F p. et p d.II F hoi I F p et p d HI F per d II F per d IV F dig I Tl b cart Abd dig [V Fig. 2. Pipilo erythrophthalmus. Lateral view of the left leg showing a deeper set or muscles. The superficial muscles iliotihialis, sartorius, gas- trocnemius and peroneus longus have been removed, X 1-5. Taxonomic Study, Avian Family Fringillidae 179 II troc. nf II. troc. med Isch. fern. Add. long (p. ont.) Pirif Add long (p post) Semim. Ext. dig. Per. brev. Tib. cort. Fig. 3. Pipilo erythrophthalmus. Lateral view of the left leg showing the still deeper muscles. In addition to those listed for figure 2, the following muscles have been wholly or partly removed: iliotrochantericus posticus, femorotibialis externus, femorotibialis medius, biceps femoris, semitendinosus, tibialis anticus, flexor perforans et perforatus digiti II, and flexor perforans et perforatus digiti III, X 1.5. 180 Untversity of Kansas Publs., Mus. Nat. Hist. Iliac II troc med II troc post II troc ont II lib Sar Fern tib med. Fern tIb int Gos (p int ) Per. long. Ext. dig. I. Tib. ant. Ext hol. Fig. 4. Pipilo ertjthrophthalmus. Medial view of the superficial muscles of the left leg, X 1-5. Taxonomic Study, Avian Family Fringillidae 181 F dig I Ti b cart II troc. ant II troc post II troc med 1 1 i acus Fern fib med Plon Ext. dig. I Ti b ant. Fig. 5. Pipilo erythrophthalmus. Medial view of the left leg showing a deeper set of muscles tlian those seen in figure 4. The following superficial muscles have been removed: ilio tibialis, sartorius, femorotibialis internus, ohturator internus, adductor longus (pars posticus), gastrocnemius, and peroneus longus, X 1.5- 182 University of Kansas Publs., Mus. Nat. Hist. Ext cot Anter lot con Poster clot, con Int cot. Anferomed con. Midme d. con. Posteromed con Fi g u r e 6 Fi g u r e 7 F per d H F p et p d F dig I Figure 8 Fi g u r e 9 Fig. 6. Pipilo erythrophthalmus. Proximal end of left tarsometatarsus and the hypotarsus, X 4. Fig. 7. Pipilo erythrophthalmus. Lateral view of proximal end of left femur and a portion of the pelvis, X 3.5. Fig. 8. Pipilo enjthrophthalmus. Upper surfaces of the phalanges of the foretoes of the left foot showing insertions of tlie M. extensor aigitorum longus, X3. Fig. 9. Pipilo erythrophthalmus. Medial view of the second digit of the left foot, showing insertions of the flexor muscles, X 3- Taxonomic Study, Avian Family Fringillidae 183 The division of the pars interna of the m. gastrocnemius into anterior and posterior parts has not been reported by previous authors yet the division is quite distinct in those birds in which it occurs. Hudson (1937:36) points out that in some non-passerine birds the pars interna is double, but that in these species the m. semimembranosus inserts between the two parts. This is not the condition in those species studied by me. Only the ploceids and the cardueline finches in the present investigation fail to show such a division. The undivided muscle in these birds resembles, in its origin and position, the posterior portion of the muscle found in those species showing the bipartite condition. The greater mass of the bipartite muscle probably makes possible a stronger exten- sion of the tarsometatarsus. Thus, the divided or undivided conditions of the m. obturator externus and the pars interna of the m. gastrocnemius seem to be correlated with the degrees of strength of certain movements of the leg. It is conceivable that these differences in structure are cor- related with the manner in which food is obtained, the birds having the bipartite muscles being those which spend the most time on the ground searching and scratching for seeds and other sorts of food. Yet, in Leucosticte, a cardueline, and in Calcarius, an emberizine, whose foraging habits are rather similar, the structure is unlike. Leucosticte does resemble the emberizines and also Piranga and Spiza in the extension of a band of muscle fibers from the pars interna of the m. gastrocnemius around tlie front of the knee. A band of muscle fibers of this sort strengthens the knee joint and gives still more strength to the pars interna. This condition has been reported in a number of birds by Hudson ( 1937 ) and is, in all probability, an adaptation for greater strength of certain leg move- ments. The development of this band in Leucosticte seems to parallel that in the other birds studied and does not indicate rela- tionship, since in Leucosticte this band arises from the undivided muscle which ( as stated above ) resembles only the posterior portion of the bipartite muscle described for the other birds. In the latter, the muscular band arises from the anterior part of the muscle. Minor differences in muscle pattern, like those already mentioned, are consistent also between subfamilies, but correlation of these minor differences with function is diflBcult. There is the implica- tion, however, that in all the groups except the carduelines and ploceids, the emphasis is on greater strength and mobility of the leg. In the carduelines that were studied the origin of the m. sartorius 184 UxnERSiTY OF Kansas Publs., Mus. Nat. Hist. does not extend so far craniad as in the other species. In the latter, at least half of the origin is from the last one or two free dorsal vertebrae; in the carduelines no more than one third of the origin is anterior to the ilium. It is conceivable that the more craniad the origin, the stronger the forward movement of the thigh would be. In Passer, Estrilda and Poephila, and in all the cardueline finches examined, the bellies of the m. flexor perforans et perforatus digiti II and the m. flexor perforans et perforatus digiti III are more inti- mately connected than they are in the other species studied. Thus, the amount of independent action of these muscles in Passer, in the estrildines, and in the carduelines probably is reduced. In Passer, the estrildines, and the carduelines the edges of the sheathlike tendon of insertion of the m. perforatus digiti III are thickened; as a result the insertion appears superficially to be double but closer examination reveals that there is a fascia stretched be- tween the thickened edges. In the other species examined, tlie insertion is sheathlike throughout and there are no thick areas. I cannot explain this on the basis of function. The difference, how- ever, is obvious and constant. Aside from the differences noted above, there were variations of muscle pattern that seem to be significant only in Vireo oUvaccus. In this species the central, aponeurotic portion of tlie m. iliotihialis is absent. The origin of the m. adductor longus et hrevis is from the dorsal edge of the ischiopubic fenestra and not from the mem- brane covering this fenestra. The origin of the pars posticus of this muscle, furthermore, is fleshy and not tendinous as it is in the other species. The m. flexor perforatus digiti II is larger and more deeply situated in Vireo and has, furthermore, no connection with the m. flexor hallucis longus. The latter muscle is smaller and weaker than in any of the other species and has only one (the posterior) head of origin. The m. flexor hallucis hrevis, on the contrary, is larger than in the other birds, compensating, probably, for the small m. flexor hallucis longus. In those differences, however, which separate the carduelines and ploceids from the otlier birds studied, Vireo resembles, in every instance, the richmondenines, emberizines, tana- gers, warblers, and blackbirds. On the basis of differences in leg-musculature the species which are now included in the Family Fringillidae may be separated into two groups. One group includes the richmondenines and the em- berizines; the other, the carduelines. The muscle patterns of the legs of the birds of the first group are indistinguishable from those of Seiurus, Icterus, Molothrus, and Piranga, and except for tlie dif- Taxonomic Study, Avian Famh^y Fringillidae 185 ferences noted are similar to those in Vireo. The carduelines, on the other hand, are similar in every point of leg-musculature to the ploceids which were studied. Thus, the heterogeneity of the Family Fringillidae, as now recognized, is emphasized by differences in the muscle patterns of the leg. Comparative Serology General Statement The application of serological techniques to the problems of animal relationships has been attempted with varying degrees of success over a period of approximately fifty years. Few of the earlier studies were of a quantitative nature, but within the past decade, satisfactory quantitative serological techniques have been developed whereby taxonomic relationships may be estimated. The usefulness of comparative serology in taxonomy has been demon- strated in investigations of many groups wherein results obtained have, in most instances, been compatible with the results obtained by more conventional methods, such as comparative morphology. As Boy den (1942:141) stated, "comparative serology . . . is no simple guide to animal relationship." However, the objectiveness of its methods, the fact that it has its basis in the comparisons of biochemical systems which seem to be relatively slow to change in response to external environmental influences, and the fact that the results are of quantitative nature favor, where possible, the inclu- sion of data from comparative serology along with that from more conventional sources when an attempt is made to determine the relationships of groups of animals. The application of serological methods in ornithology has not been extensive. Irwin and Cole (1936) and Cumley and Irwin (1941, 1944) used two species of doves and their hybrids and demonstrated that a distinction between the red cells of these birds could be made by use of immunological methods involving the ag- glutinin reaction. McGibbon (1945) was able to distinguish the red cells of interspecific hybrids in ducks by similar methods. Irwin (1953) used similar techniques in his study of the evolutionary patterns of some antigenic substances of the blood cells of birds of the Family Columbidae. Sasaki (1928) demonstrated the useful- ness of the precipitin technique in distinguishing species of ducks and their hybrids. This technique was used successfully also by DeFalco (1942) and by Martin and Leone (1952). Working with groups of known relationships, these investigators showed that the "accepted" systematic positions of certain birds were confirmed by 186 Umv-ersity of Kansas Publs., Mus. Nat. Hist. serological procedures. The precipitin reaction, however, has never been applied to actual problems in avian taxonomy prior to the present study. Preparation of Antigens Although most previous work in comparative serology in which precipitin tests were used has involved the use of whole sera as antigens, Martin and Leone (1952) indicated that tissue extracts are satisfactory as antigens and that serological differentiation can be obtained with these extracts and the antisera to them. I decided, therefore, to use such extracts in these investiga- tions, since the small sizes of the birds to be tested made it impracticable to obtain enough whole sera. Most of the birds used were obtained by shooting, but a few were trapped and the exotic species were purchased alive from a pet dealer. When a bird was killed, the entire digestive tract was carefully removed to prevent the escape of digestive enzymes into the tissues and to prevent putrefaction by action of intestinal bacteria. As soon as possible (and within three hours in every instance) the bird was skinned, the head, wings, and legs were removed, and the body was frozen. Each specimen, consisting of trunk, heart, lungs, and kidneys, was wrapped separately and carefully in aluminum foil to prevent dehydration of the tissues. The specimens were kept frozen until the time when the extracts were made. When an extract was to be prepared, the specimen was allowed to thaw but not to become warm. In the cold room with tlie temperature of all equipment and reagents at 2''C., the specimen was placed in a Waring blender with 0.9 per cent aqueous solution of NaCl buffered with M/150 K2HPO4 and M/150 Na2HP04 to a pH of 7.0. The amount of reagent used was 75 ml. of saline for each gram of tissue to be extracted. The tissues were minced in the blender, allowed to stand at 2°C. for 72 hours, and the tissue residues removed by centrifugation in a refrigerated centrifuge. Formalin was added to a portion of the supernatant in the amount necessary to make the final dilution 0.4 per cent. This formolization was found to be necessary to inhibit the action of autolytic enzymes over the period of time required to complete the investigations. The effects of formolization on the antigenicity and reactivity of proteins are dis- cussed later. It was necessary to sterilize and clarify the "native" (unformo- Hzcd) extracts; this was done by filtration through a Scitz filter. These "native" substances were used only in the early stages of the investigation (see below). The filtrate was bottled and stored at 2°C. In the early stages of this in- vestigation clarification of the formolized extract was accomplished by the same sort of filtration. It was determined, however, that centrifugation in a re- frigerated centrifuge at high speeds (I7,000g) served the same purpose and was quicker. The formolized extracts were bottled and also stored at 2°C. (although refrigerated storage of the formolized extracts docs not seem neces- sary). For each extract the amount of protein present was determined colori- metrically by the method of Greenberg (1929) with a Leitz Photrometer, Species for which extracts were prepared and the protein values of the extracts arc listed in Table 1. Extracts of some species were used throughout most of the experiment; extracts of others were used only when needed for purposes of comparison. Taxonomic Study, Avian Family Fringillidae 187 Table 1. — Species from Which Extracts Were Prepared and Injection Schedules for Extracts Against Which Antisera Were Produced Species Protein, gms. per 100 ml. Injection schedules for production of antisera Myiarchiis crinitus (Linnaeus) 0.65 Series 1: Intravenous, 0.5, 1.0, 2.0, and 4.0 ml. Passer domesticus 1.40 Series 1: Subcutaneous, 0.5, 1.0, 2.0, and 4.0 ml. Estrilda amandava 0.45 *Series 1: Intravenous, 0.5, 1.0, 2.0, and 4.0 ml. *Series 2: Subcutaneous, 0.5, 1.0, and 2.0 ml. Intraperitoneal, 8.0 ml. Poephila guttata 0.56 *Same as for Estrilda. Molothrus aier 0.65 Series 1: I nta venous and subcutaneous, respective!}', 0.5 and 0.5 ml., 1.0 and 1.0 m.l., 3.0 and 1.0 ml., 5.0 and 3.0 ml. Series 2: Subcutaneous, 0.5, 1.0, 2.0 and 4.0 ml. Piranga rubra 0.50 Same as for Molothrus. Richmondena cardinalis. . 0.70 *Same as for Estrilda. Richmondena cardinalis. . 0.60 Same as for Spinus. Passerina cyanea 0.45 Antiserum not prepared. Spiza americana 0.70 Same as for Molothrus. Carpodacus purpureus. . . 0.50 Antiserum not prepared. Spinus tristis 0.49 Series 1: Intravenous, 0.5, 1.0, 2.0, and 4.0 ml. Series 2: Intravenous, 0.5, 1.0, 2.0, and 4.0 ml. Series 3: Subcutaneous, 0.5, 1.0, 2.0, and 4.0 ml. Pipilo erythrophthalmus. . 0.92 Antiserum not prepared. J unco hyemalis 0.56 Same as for Spimts. Spizella arborea 0.48 Same as for Spinus. Zonotrichia querula 0.48 Same as for Spinus. Zonoirichia albicollis. . . . (Gmelin) 0.92 Antiserum not prepared. * Antiserum prepared against formolized antigen. 18S University of Kansas Publs., Mus. Nat. Hist. Preparation of Antisera All antisera were produced in rabbits (laboratory stock of Oryctolagus cuniculus). Three methods of injection of antigen were used in various com- binations: intravenous, subcutaneous, and intraperitoneal. Injection schedules used in the production of each antiserum are listed in Table 1. Both formo- lized and "native" antigens were used. Each rabbit received one or more series of four injections, each injection being administered on alternate days and dou- bling in amount: 0.5 ml., 1.0 ml., 2.0 ml., and 4.0 ml. In all but two instances more than one series of injections was necessary to produce a useful antiserum. More than two series, however, resulted in little or no improvement of the reactivity of the antiserum. The injection-series were separated by intervals of eight days. On the eighth day after the last injection of each series, 10 ml. of blood were withdrawn from the main artery of the ear of the rabbit, and the antiserum was used in a homologous precipitin test to determine its usefulness. If the antiserum con- tained sufficient amounts of antibodies to conduct the projected tests, the rabbit was completely exsanguinated by cardiac puncture, by using an 18-gauge needle and a 50 ml. syringe. The whole blood was placed in clean test tubes and allowed to clot. It was allowed to stand at 2°C. for 12 to 18 hours so that most of the serum would be expressed from the clot. The serum was then decanted, centrifuged to remove all blood cells, sterilized in a Seitz filter, bottled in sterile vials, and stored at 2°C. until used. Methods of Serological Testing The precipitin reaction is the most successful of the serological techniques thus far devised for systematic comparisons. The reaction occurs because antigenic substances introduced into the body of an animal cause the formation of antibodies which precipitate antigens when the two are mixed. The antisera which are produced show quantitative specificities in their actions; therefore, when an antiserum containing precipitins is mixed with each of several antigens, the reaction involving the homologous antigen (that used in the production of the antiserum) is greater than those reactions involving the heterologous anti- gens (antigens other than those used in the production of the antiserum). Furthermore, the magnitudes of the reactions between the antiserum and the heterologous antigens vary according to the degrees of similarity of these antigens to the homologous one. The method of precipitin testing follows that outlined by Leone ( 1949). The Libby (1938) Photronreflectometer was used to measure the turbidities de- veloped by the interaction of antigen and antiserimi. With this instrument parallel rays of light are passed through the turl)id systems being measured. Light rays are reflected from the suspended particles to the sensitive plate of a photoelectric cell; this generates a current of electricity which causes a deflec- tion on a galvanometer. The deflection is proportional to the amount of turbidity developed and readings may be taken directly from the scale of the instrument. The reaction-cells of the photronreflectometer are designed to operate with a volume of 2 ml.; therefore, this volume was used in all testing. In every series of tests the amount of antiserum was held constant and the amoimt of antigen was varied. The volume for each antigen dilution was always 1.7 ml., and to tills was added 0.3 ml. of antiserum to make up a volume of 2 ml. Taxonomic Study, Avian Family Fringillidae 189 Antigens were diluted with 0.9 per cent phosphate-bufFered saline solution. Tests were run in standard Kolmer test-tube racks, each test consisting of 12 tubes. Each dilution was made on the basis of the known protein concentra- tion of the antigen. The first tube contained an initial dilution of 1 part protein in 250 parts saline and each successive tube contained a protein dilution one- half the concentration of the preceding tube, ranging up to 1:512,000. Saline Table 2. — Percentage values obtained from analyses of precipitin reactions. Numerals represent relative amounts of reaction between antigens and antisera. Homologous reactions are arbitrarily valued as 100 per cent, and heterologous reactions are expressed accordingly. Comparisons are meaningful only if made within each, horizontal row of values. Antigens ANTISERA C3 :§ r-'^ Eq 5 O 8 e e ft5 C3 I.. N Pi. t>2 S to C3 s «> §. Passer domesticus . Estrilda amandava . 75 74 73 66 81 72 100 88 75 79 72 53 81 Poephila guttata . Molothrus ater . 95 100 77 67 87 81 66 54 69 65 86 75 69 75 Piranga rubra . 100 89 Richmondena cardinalis . 75 80 91 100 98 65 88 91 Spiza americana . 65 68 71 100 64 67 80 Carpodacus purpureus . Spinus tristis . 70 71 71 61 89 93 72 74 73 60 89 100 53 60 70 Junco hyemalis . 64 56 74 65 87 68 100 Zonotrichia querula . 65 71 67 89 75 100 controls, antiserum controls, and antigen controls were maintained with each test to determine the turbidities inherent in these solutions. These control- turbidities were deducted from the total turbidity developed in each reaction- tube, the resultant turbidity then being considered as that which was caused by the interaction of antigens and antibodies. The turbidities were allowed to develop over a 24-hour period. In the early stages of this investigation the reactions were allowed to take place at 2° C. in order to inhibit bacterial growth. 3—4632 190 Unr'ersity of Kansas Publs., Mus. Nat. Hist. Later tests were carried out at room temperatures, and bacterial growth was prevented by the addition to each tube of 'Mertliiolate' in a final dilution of 1:10,000. Experimental Data Corrected values for the turbidities obtained were plotted with the turbidity values on the ordinate and the antigen dilutions on the abscissa. The homolo- gous reaction was the standard of reference for all other test reactions with the same antiserum. By summing the plotted turbidity readings, numerical values are obtained which are indices serving to characterize the curves. Such values were converted to percentage values, that of the homologous reaction being considered 100 per cent. These values, plus the curves, provide the data by means of which the proteins of the birds may be compared. Plots representa- tive of the precipitin curves are presented in Figs. 10 to 21. For convenience each plot represents only several of the 10 curves obtained vdth each antiserum. A summary of the serological relationships of the birds involved in the precipitin tests is presented in Table 2, in which percentage values are pre- sented. Since the techniques involved in testing were greatly improved as the investigation proceeded, the summary is based solely on those tests run in the later stages of the investigation. For reasons which will become apparent in later discussion, it should be emphasized that in Table 2 comparisons may be made only within each horizontal row of values. Discussion of the Serological Investigations One of the problems met early in this investigation was instability of the proteins in the extracts that were prepared. Extracts in which no attempt was made to inactivate the enzymes present proved un- satisfactory. It was necessary to maintain the temperature of the "native" antigens at 2°C., and all work with such antigens had to be performed at this temperature. This arrangement was inconvenient; furthermore, inactivation of the enzymes was not complete even at this low temperature, and some denaturation of the proteins took place as evidenced by the gradual appearance of insoluble pre- cipitates in the stored vials. The preservatives, 'Merthiolate' and formalin, were used in an attempt to inhibit tlie autolytic action of the enzymes present. Formalin, when added to make a final dilution of 0.4 per cent, proved to be the more satisfactory of the two preservatives and was used throughout most of the work. Formalin caused slight de- naturation of some of the proteins, but this effect was complete within a few hours, after which any denatured material was re- moved by filtration or centrifugation. The proteins remaining in solution were stable over the period necessary to complete the in- vestigations. The addition of formalin reduces the reactivity of the extracts when they are tested with antisera prepared against "native" anti- Taxonomic Study, Avian Family Fringillidae 191 gens and causes changes in the nature of the precipitin curves. This eflFect has been pointed out by Horsfall ( 1934) and by Leone ( 1953) in their work on the effects of formaldehyde on senim proteins. Their data indicate, however, that even though changes in the immunological characteristics of proteins are brought about by form- olization, the proteins retain enough of their specific chemical char- acteristics to allow consistent differentiation of species by immuno- logical methods. In the tests which I performed, the relative posi- tions of the precipitin curves, whether native or formolized extracts were involved, remained unchanged (Figs. 10, 11). All data used in interpretation of the serological relationships were obtained from tests in which formolized antigens of equivalent age were used. Only three antisera were produced against formolized antigens, all others being produced against "native" extracts. The formolized antigens seemed to have a greater antigenicity, in most instances, than did those which were unformolized, and precipitin reactions involving antisera produced against formolized antigens developed higher turbidities. The antisera produced against formolized anti- gens were equal to but no better than those prepared against "native" extracts in separating the birds tested (Figs. 12, 13). The rabbit is a variable to be considered in serological tests. Two rabbits exposed to the same antigen, under the same conditions, may produce antisera which differ greatly in their capacities to dis- tinguish different antigens. It is logical to assume, therefore, that two rabbits exposed to different antigens may produce antisera which also differ in this respect. This explains the unequal values of reciprocal tests shown in Table 2. Thus, in the test involving the antiserum to the extracts of Richmondena, a value of 71 per cent was obtained for Spiza antigen, whereas in the test involving anti- Spiza serum, a value of 98 per cent was obtained for Richmondena antigen. In Table 2, therefore, comparisons may be made only among values for the proteins of birds tested with the same anti- serum. Since the amount of any one antiserum is limited, there is, of ne- cessity, a limit as to the number of birds used in a series of serological tests. Therefore, although the results reveal the actual serological relationships of the individual species, interpretation of the relation- ships of the taxonomic groups must be undertaken with the realiza- tion that such an interpretation is based on tests involving relatively few species of each group. It is reasonable to assume, however, that a species which has been placed in a group on the basis of re- semblances other than serological resemblance would show greater 192 University of Kansas Publs., Mus. Nat. Hist. serological correspondence to other members of that group than it would to members of other groups. Specifically, in the Fringillidae and their allies, there seems to be little reason to doubt that genera, and even subfamilies, are natural groups. This is illustrated in tests involving closely related genera: Richmondena and Spiza (Figs. 14, 15, 18), EstriJda and Poephila (Fig. 21), Spinus and Carpodacus (Figs. 12, 17, 19, 20). In each of these tests the pairs of genera mentioned show greater serological correspondence to each other than they do to other kinds involved. This point is illustrated fur- ther by a test (not illustrated) involving Zonotrichia querula (the homologous antigen) and Zonotrichia albicollis. Although this test was one of an earlier series in which difficulties were encountered (the data, therefore, were not used), it is of interest that the two species were almost indistinguishable serologically. The serological homogeneity of passeriform birds is emphasized by the fact that the value of every heterologous reaction was more than 50 per cent of the value of the homologous reaction, except in the test involving the anti-Richmondena serum and Myiarchus (Fig. 13 ) in which the value of the heterologous reaction was 45 per cent. Because most ornithologists consider these genera to be only dis- tantly related (they are in dijBFerent suborders within the Order Passeriformes ) , the relatively high value of the heterologous reac- tion emphasizes the close serological correspondence of passerine birds and indicates that small consistent serological diflFerences among these birds are actually significant. The possibility that some of the serological correspondence is due to the "homologizing" eflFect of formalin on proteins should not be excluded. I think, how- ever, that this eflFect is not entirely responsible for the close corre- spondence observed here. An additional point to consider in interpretation of the serological tests is that the techniques used tend to separate sharply species that are closely related whereas species that are distantly related are not so easily separated. In other words, comparative serological studies with the photronreflectometer tend to minimize the differences be- tween distant relatives and to exaggerate the differences between close relatives. In analyzing the serological relationships of the species used in this study, it becomes obvious that two or more series of tests must be considered before the birds can be placed in relation to each other. For example, the data presented in Fig. 14 indicate that Spiza and Molothrus show approximately the same degree of sero- logical correspondence to Richmondena. This does not imply neces- Taxonomic Study, Avian Family Feingillidae 193 sarily that Spiza and Molothrus are closely related. If Fig. 15 is examined, it can be determined that Richmondena shows much greater serological correspondence to Spiza than does Molothrus. Thus, an analysis of both figures serves to clarify the true serologi- cal relationships of the three genera. By reference to other series of tests involving these three birds a more exact determination of their relationships may be obtained. To illustrate this point by a hypothetical example, two species might seem equidistant, serologically, from a third species. Addi- tional testing should indicate if the first two species are equidistant in the same direction (therefore, by implication, close relatives) or in opposite directions (therefore, distant relatives). A single test supplies only two dimensions of a three dimensional arrangement. It is impossible to interpret and to picture the serological data satisfactorily in two dimensions; therefore, a three-dimensional model (Figs. 22, 23) was constructed to summarize the serological relationships of the birds involved. Each of the eleven kinds used consistently throughout the investigation is represented in the model. By use of the percentage values (Table 2), each bird was located in relation to the other birds. Where possible, averages of reciprocal tests (Table 3) were used in determining distances between the elements of the model. In this way seven of the birds were ac- curately located in relation to each other. Lacking reciprocal tests, the positions of the other birds were determined by the values of single tests ( Table 4 ) . Although these birds were placed with less certainty, at least four points of reference were used in locating each species. At least one serological test is represented by each con- necting bar in the model. The lengths of the bars connecting any two elements were determined as follows: a percentage value (Table 3 and Table 4) representing the degree of serological cor- respondence between two birds was subtracted from 100 per cent; the remainder was multiplied by a factor of five to increase the size of the model and the product was expressed in millimeters; a bar of proper length connects the two elements involved. From the model it is observed that, Molothrus and Passer ex- cluded, the birds fall into two distinct groups : one includes Piranga, Richmondena, Spiza, Junco, and Zonotrichia; the other includes Estrilda, Poephila, Carpodacus, and Spinus. Within the richmondenine-emberizine-thraupid assemblage, Junco and Zonotrichia constitute a sub-group apart from the others. Piranga and Richmondena show close serological correspondence. The present taxonomic position of Spiza in the Richmondeninae, 194 University of Kansas Publs., Mus. Nat. Hist. Table 3. — Reciprocal Values Used to Determine Distances Between Elements of the Model; Each Value Represents the Average of Sero- logical Tests Between the Species Involved Estrilda amandava . Poephila guttata . C5 C3 5 CO 92 ta> 92 ft5 74 72 72 78 78 s 59 s N3 Richmondena cardinalis . Spiza americana . 74 85 63 72 78 85 77 77 77 79 85 Spimis tristis . 72 78 63 77 Junco hyemalis . Zonotrichia querula. 77 77 79 85 Table 4. — Single Values Used to Determine Distances Between Ele- ments OF the Model; Each Value Represents a Single Test Between the Species Involved •2 e -c; ^ e c 1^ « 1 s o o ^ e (3 5} C •- 6 o CQ V 1 a. »- f 2 4 6 8 10 ANTIGEN DILUTION TUBES Figure 16 Richmondena 1- — Spiza — 'O — Piranga — • — Zonotrichia 12 .'■15-, o IT + /^ \ ^\ ^nU-Spua ///"• r? V ij %\ i- <1 \V ' 1 "X^ V \ 1 f \\ \ ^ 2 4 6 8 10 ANTIGEN DILUTION TUBES Figure 15 12 < o >- 1- 4 3 /S>^ Ani\-i/unco 2 4 6 8 10 12 ANTIGEN DILUTION TUBES Figu re 17 — C3 — Junco — ^ — Mololhrus Carpodacus ° Spinas Figs. 14-17. Graphs of precipitin reactions illustrating serological relation- ships. For further explanation, see text, pp. 190-193. Fig. 14. Serological relationships of Richmondena, Spiza, and Molothrus. Fig. 15. Serological relationships of Richmondena, Spiza, and Molothrus. Fig. 16. Serological relationships of Carpodacus with the richmondenine- emberizine-thraupid assemblage. Fig. 17. Serological relationships of Carpo- dacus and Spinus with Richmondena and Junco. Taxonomic Study, Avian Family Fringellidae 197 Ar\U-Spiza 10 - < o ?- 5 CD 3 I2r 2 4 6 8 10 12 ANTIGEN DILUTION TUBES Figure 18 - / °\ knW-Pirango c 'h\ / o h \ '^7 o^ \\ ■If o/, '1 M\ 1 \A°^ jl o^\\ < o m 26r 2 4 6 8 10 12 ANTIGEN DILUTION TUBES Figure 19 A 2 4 6 8 10 ANTIGEN DILUTION TUBES Figu re 20 Richmondena 1 SpUa — O — Piranga 2 4 6 8 10 ANTIGEN DILUTION TUBES Figure 21 — I — Poephila — ^ — Estrilda Carpodacus Spin us Figs. 18-21. Graphs of precipitin reactions illustrating serological relation- ships. For further explanation, see text, pp. 190-193. Fig. 18. Serological relationships of Spinus and Poephila with the rich- mondenines. Fig. 19. Serological relationships of Carpodacus and Spinus with Richmondena and Piranga. Fig. 20. Serological relationships of Poephila and Richmondena with the carduehnes. Fig. 21. Serological relationships of Richmondena and Spinus with the estrildines. 4—4632 198 Unrtrsity of Kansas Publs., Mus. Nat. Hist. Fig. 22. Two views of a model illustrating serological relationships among fringillid and related birds. For furtlier explanation, see text, pp. 193-194. Genera Pi .... Firanfia C E J M Pa Carpoclacus Estrilda Po . . R . . . . Poenhila . . Riclunomlena Jimco Molothrus Passer Sn . . Sz . . Z . . . . S])iniis . . Spiza . . Zonotricliia Taxonomic Study, A^^AN Family Fringillidae 199 Fig. 23. Two additional views of the model shown in fig. 22 illustrating serological relationships among fringiUid and related birds. For further ex- planation, see text, pp. 193-194. Genera Pi .... Piransa c . . . . Carpodacus Po . . . . Poephila E . . . Estrilda R . . . . Richmondena J . . Junco Sn . . . . Spinus M . . . Molothrus Sz . . . . Spiza Pa . . . Passer Z . . . . Zonotrichia 200 University of Kansas Publs., Mus. Nat. Hist. which has been questioned by Beecher (1951a: 431; 1953:309), is corroborated at least insofar as the serological evidence is concerned. Certainly, serological correspondence of Spiza with tlie richmon- denine-emberizine-thraiipid assemblage is greater than with any other group of birds tested. It is obvious that the serological affinities of tlie carduelines do not lie with the richmondenines, emberizines, or thraupids. The carduelines show greater serological correspondence with the estrildines than they do with any of the other groups tested. Fur- tlier serological investigation involving other species, however, is necessary before the nearest relatives of the cardueHnes can be de- termined with certainty. The two estrildines tested {Estrilda and Poephila) show close serological relationship. Their nearest relatives, serologically, seem to be the carduelines. The classification (Wetmore, 1951) that places Passer in the same family with the estrildines is not upheld by the serological data available. Passer is not, serologically, closely related to any of the birds tested. It is of interest that Beecher (1953:303-305), on the basis of jaw musculature, places Passer and the estrildines in separate famiHes (Ploceidae and Estrildidae, re- spectively ) . Molothrus shows greater serological correspondence to the rich- mondenine-emberizine-thraupid assemblage than to any of the other birds tested. It is definitely set apart from this group, however, and its position, serologically, is compatible with that based on evidence from other sources. There seems to be but little argument among ornithologists that icterids, fringillids, and ploceids constitute families which are dis- tinct from one another. If, then, the serological differences between Molothrus (Icteridae) and Richmondena (Fringillidae), between Molothrus and Zonotrichia (Fringillidae), and between Rich- mondena and Poephila (Ploceidae) are indicative of family dif- ferences, there are four families represented by the birds involved. Molothrus represents one family; Piranp,a, Richmondena, Spiza, Junco, and Zonotrichia, a second; Estrilda, Poephila, Carpodacus, ' and Spinus, a third; and Passer, a fourth. Taxonomic Study, Avian Family Fringillidae 201 Conclusions The heterogeneity of the Family Fringillidae has been emphasized by many authors. The relationships of the species now included in this Family have been the subject of much discussion and con- stitute an important problem in avian systematics. Sushkin's studies ( 1924, 1925 ) of features of the homy and bony palates have served as a basis for the present division of the Family into subfamilies. Recently, Beecher (1951a, 1951b, 1953) and TordoflF (1954) have used these features and others which they thought to be of value in an attempt to clarify the relationships of the species involved. Beecher's work (1951a, 1951b, 1953) on jaw-musculature is a valuable contribution to our knowledge of the anatomy of passerine birds. His myological studies were so thorough and his presenta- tion so detailed that students who disagree with his interpretations can draw their own conclusions. Beecher (1951b: 276) points out that there are two basic types of skeletal muscle — those with parallel fibers and those with pinnately arranged fibers. The muscles with pinnate fibers seem to be more efficient, each muscle having a greater functional cross section for its bulk than does one with parallel fibers. He assumes that muscles with parallel fibers are more primitive, phylogenetically, than are those with fibers ar- ranged pinnately. Since his study of the jaw muscles of the Icteridae (1951a) revealed that patterns of jaw-musculature within this Family remain constant regardless of the methods used in procur- ing food, he assumes that such patterns may be used as indicators of relationship throughout the entire oscinine group. These two assumptions, then, serve as the basis for his hypothesis concerning relationship and phylogeny within this assemblage. Beecher (1951b: 278-280; 1953:310-312) maintains that within the Family Thraupidae there are two main lines which lead with almost no dis- junction to the Carduelinae and Richmondeninae. The thraupid- richmondenine line involves a shift in the nature of the m. adductor mandibulae externus siiperficialis, which becomes more pinnate in the richmondenines. This results in greater crushing power. The thraupid-cardueline line involves a shift in emphasis from the m. adductor mandibulae externus medialis to the m. pseudotemporalis superficialis and the forward advance of the insertion of the latter. This, also, promotes greater crushing ability. He states that features of the horny palate and of the plumage provide further evidence of close relationship of these groups. He includes, therefore, the 202 University of Kansas Publs., Mus. Nat. Hist. Thraupinae, the Carduelinae, and the Pyrrhuloxiinae ( r=Richmond- eninae) in the Family Thraupidae. Beecher (1953:307) indicates that the patterns of jaw-musculature of the Parulinae (wood war- blers) and Emberizinae (buntings) are similar and suggests that the buntings had their origin from the wood warblers. He includes these subfamilies, therefore, in the Family Paruhdae. Beecher's reasoning may be criticized on several points. It may be, as he suggests, that muscles with parallel fibers evolved earlier, phylogenetically, than did muscles with pinnate fibers, but he does not give adequate consideration, it seems to me, to the possibility that parallel fibers may also have evolved secondarily from pinnate fibers. Since Beecher (1951a) found that patterns of jaw-muscula- ture within the Family Icteridae were conservative, he is reluctant to admit the possibility of convergence among any of the other families. DifiFerences in patterns of jaw-musculature are, however, functional adaptations and like the bill, which is also associated with food-getting may be subject to rapid evolutionary change. Finally, in attempting to classify the oscines, he has relied almost entirely on a single character — the pattern of jaw-musculature. Tordoffs attempts ( 1954 ) to clarify the relationships of the frin- gillids and related species are based chiefly on features of the bony palate. He assumes that since palato-maxillaries seem to be absent in the majority of passerine birds, their occurrence in certain nine- primaried oscine groups indicates relationship among these groups. He points out that these bones, when present, are important areas of origin of the m. ptenjgoideiis which functions in depression of the upper jaw and in elevation of the lower jaw. He assumes, there- fore, that palato-maxillaries were evolved to provide for a more effective action of the m. pterygoideus. The need for such action could be associated with a seed-eating habit. All richmondenines and emberizines possess palato-maxillary bones either free or fused to the prepalatine bar, but there is no trace of these bones in the carduelines. Carduelines, furthennore, possess prepalatine bars that are characteristically flared anteriorly. This condition does not exist in the richmondenines or in the emberizines. Tordoff points out, also, that the irregular, erratic migrations of the New World Carduelinae are unlike the more regular migrations of the richmondenines and emberizines. The carduelines, further- more, are more arboreal in their habits than are these other groups and exhibit a decided lack of nest sanitation during the later stages of nesting, a situation which contrasts with that found in the Rich- Taxonomic Study, Avian Family Fringillidae 203 mondeninae and Emberizinae. He suggests, therefore, that the carduelines are not so closely related to the richmondenines and the emberizines as previously has been thought. Since there are only two cardueline genera, Loximitris and Hes- periphona, endemic to the New World and at least 10 genera with many species endemic to the Old World, Tordoff (1954:15) sug- gests an Old World origin for the carduelines. He strengthens his argument for this hypothesis by pointing out that in features of the bony palate and in habits the carduelines resemble the estrildines of the Family Ploceidae. Tordoff (1954:29-30) states that the tanagers not only merge with the richmondenines but also grade imperceptibly into the ember- izines. He includes, therefore, the Richmondeninae, Emberizinae, and Thraupinae in the Family Fringillidae. He suggests that the carduelines are ploceids, closely related to the Subfamily Estrildinae, on the basis of structure of the bony palate, geographic distribution, social behavior, and habits such as nest-fouling and nest-building. Tordoff, like Beecher, has based his interpretations chiefly on one feature — structure of the bony palate. Since this feature also is associated with food-getting, the possibilities of convergence of dis- tantly related species with similar habits and divergence of closely related species with different habits may not be excluded. The hazard of unrecognized adaptive convergence cannot, of course, be excluded from most fields of taxonomic research, but some features of morphology and biochemistry are notably more conservative than others and undergo slower evolutionary change. Such features are often of utmost importance in distinguishing the higher taxonomic categories. Most ornithologists are aware that, within the Order Passeri- formes, patterns of musculature in the leg have evolved at a slow rate and exhibit little variation within the Order. Differences which do occur, therefore, probably are significant, especially those that are consistent between groups of species. As I have pointed out earlier (p. 184), there are no significant differences in leg-musculature between the Richmondeninae, Emberizinae, and Thraupidae. In- deed, it is difficult to define these groups on the basis of leg-muscu- lature. If these groups are of common origin, the lack of distinct boundaries between them is not surprising. A muscular band which extends from the pars interna of the m. gastrocnemius around the front of the knee is present in every emberizine species that I studied and in the Genus Piranga. With the exception of Spiza none of the richmondenines possesses this band. 204 University of Kansas Publs., Mus. Nat. Hist. The significant differences in leg-musculature which have been discussed above (pp. 183-184) distinguish the carduelines from the New World finches and tanagers. Even the carduehne Leucosticte and the emberizine Calcarius, which resemble one another in gen- eral adaptations and in several myological features of the leg (p. 183), agree in significant features of the musculature with the re- spective groups to which they belong. The carduelines agree in the major features of leg-musculature with the ploceids which I studied. The use of serological techniques in taxonomic work has two main advantages. The biochemical systems involved in such in- vestigations seem to be relatively slow to change in response to ex- ternal environmental influences, and the quantitative nature of the results obtained makes possible objective measurement of resem- blances among species. I have pointed out (p. 200) that the carduelines are excluded, serologically, from the distinct assemblage formed by the richmond- enines, emberizines, and tanagers. Actually, the carduelines show less serological resemblance to this assemblage than do the estril- dines, and most ornithologists agree that the Estrildinae are not at all closely related to the Richmondeninae, Emberizinae, and Thraup- idae. Molothriis, representing a family (Icteridae) recognized as distinct from the Family Fringillidae, also more closely resembles the fringilhd assemblage, serologically, than do the carduelines. Al- though the Carduelinae constitute a distinct group serologically, they show greater serological resemblance to the estrildines of the Family Ploceidae than to any of the other species tested. At least the carduelines and the estrildines form a group as compact as the subfamilies of the Fringillidae. Thus, the serological data correlate well with those obtained from the study of the leg-musculature. Present systems of classification include the subfamilies Passerinae and Estrildinae in the Family Ploceidae. Passer, however, is less closely related to the estrildines serologically than are the cardue- lines, and is less closely related to the estrildines than Molothrus, an icterid, is to the fringillids. This raises a question as to the homo- geneity of the Family Ploceidae as presently recognized by most ornithologists. If the Passerinae and the Estrildinae are placed in a single family, the serological divergence among members of this group is certainly greater than it is in the Family Fringillidae. Addi- tionally, Beecher (1953:303-304) found that the estrildines possess a pattern of jaw-musculature different from those in other ploceids. Taxonomic Study, Avian Family Fringillidae 205 The combined evidence from jaw-musculature and serology has caused me to conclude that the estrildines should be excluded from the Family Ploceidae ( see below ) . In an attempt to clarify the relationships of the Fringillidae and allied groups, I here review briefly the evidence which has been presented. From his studies of jaw-musculature (1951a, 1951b, 1953) Beecher concludes that the Pyrrhuloxinae (=Richmond- eninae), the Carduelinae, and the Thraupinae are closely related. He places these groups in the Family Thraupidae. He excludes the Emberizinae from this group and places them with the wood war- blers in the Family Parulidae. He suggests that the estrildines con- stitute a family ( Estrildidae ) separate from the Family Ploceidae. From his studies of certain features of the bony palate TordofiF (1954:25-26, 32) concludes that the richmondenines, the ember- izines, and the tanagers have a common origin and places these groups in the Family Fringillidae. He excludes the carduelines from this assemblage, suggests that they are closely related to the estril- dines, and includes them as the Subfamily Carduelinae in the Family Ploceidae. In this paper I have presented data obtained from the study of certain features of morphology and biochemistry which I think are less subject to the influence of environmental factors than those features studied by recent workers. It is significant that the data obtained by use of serological techniques and those obtained from the study of leg-musculature point to the same conclusions. On the basis of these data I have drawn several conclusions concerning the relationships of the groups which I studied. The richmondenines, emberizines, and tanagers are closely re- lated and should be included in a single family, Fringillidae. The Carduelinae and the Estrildinae are closely related subfamilies. Al- though most recent classifications place the Estrildinae and Pas- serinae in the Family Ploceidae, the serological evidence indicates that these groups are not closely related. Beecher (1953:303-304) drew the same conclusion from his study of jaw-musculature (see above). I suggest, therefore, that the Carduelinae and the Estril- dinae be placed in a family separate from the Ploceidae and that the name Carduelidae (rather than Estrildidae) be used for this group. At present, neither is an accepted family name. Because Carduelis Brisson 1760 is an older name than Estrilda Swainson 1827 and because Carduelis seems to be a centrally located genus in the family, I have chosen the former ( although the International 206 University of Kansas Publs., Mus. Nat. Hist. Rules of Zoological Nomenclature do not specify that priority must apply in forming family names). I have been unable to study any of the species included in the subfamilies Fringillinae (not Fringillinae of TordoflF, see 1954:23-24, and below) and Geospizinae of recent classifications; thus these groups have not been discussed above. Beecher (1953:307-308) includes Fringilla in the Subfamily Carduelinae; he includes the geospizines in a separate family, Geospizidae, and states that they are derived from the emberizines. TordoflF (1954:23-24) found that in features of the bony palate Fringilla and the geospizines resemble the emberizines and, on this basis, includes them in the Subfamily Fringillinae. The Dickcissel, Spiza americana, possesses certain features which merit special discussion. Beecher (1951a:431; 1953:309), on the basis of jaw-musculature, considers it an icterid. To be sure Spiza is in many ways an aberrant member of the group to which it is now assigned (Subfamily Richmondeninae). Spiza, serologically, is closely related to all species of the richmondenine-emberizine- thraupid assemblage. Within this assemblage its nearest relatives are the richmondenines. Spiza diflFers from the other richmond- enines studied and resembles the emberizines and tanagers in the possession of the muscular band which extends from the pars interna of the m. gastrocnemius around the front of the knee. This band, in Spiza, is smaller, however, than in any of the other species. No icterid dissected possesses such a structure. TordoflF (1954:29) states that Spiza is typically richmondenine in palatal structure and makes the suggestion, with which I agree, that Spiza is a richmond- enine and may be closely related to the ancestral stock which gave rise to the fringilhd assemblage. The serological position of Spiza, approximately equidistant from the other fringillids (Figs. 22, 23), and the presence of the small muscular band around the front of the knee constitute evidence supporting the central position of Spiza. After consideration of evidence from the studies of external mor- phology, ethology, myology, osteology, and serology, I propose here an arrangement of