Life History and Ecology of the Five-Lined Skink, Eumeces Fasciatus

Part 1

Produced by Chris Curnow, Tom Cosmas, Joseph Cooper and the Online Distributed Proofreading Team at http://www.pgdp.net

Transcriber's Note - Text Emphasis

Text - Italic

UNIVERSITY OF KANSAS PUBLICATIONS

MUSEUM OF NATURAL HISTORY

Volume 8, No. 1, pp. 1-156, 2 pls., 26 figs. in text, 17 tables September 1, 1954

Life History and Ecology of the Five-lined Skink, Eumeces fasciatus

HENRY S. FITCH

UNIVERSITY OF KANSAS LAWRENCE 1954

UNIVERSITY OF KANSAS PUBLICATIONS, MUSEUM OF NATURAL HISTORY

Editors: E. Raymond Hall, Chairman, A. Byron Leonard, Robert W. Wilson

Volume 8, No. 1, pp. 1-156, 2 pls., 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

Henry S. Fitch

Introduction

The common five-lined 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 fasciatus, actually were three closely related and similar, partly sympatric species. Although Taylor's work was careful and detailed, 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-lined 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 from the Reservation, the five-lined skink is one of those most frequently noticed in the field. In actual numbers it is probably exceeded only by the cricket frog (Acris gryllus), 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 inactive 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, Dennis G. Rainey and Lewis L. Sandidge. Mr. Robert Gordon very kindly furnished information on specimens in the Tulane University 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 suggestions 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.

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 likewise 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 effective 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 escaped. 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 sometimes 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 1/8 inch wire mesh, six or seven inches long, and three or four inches in diameter, with funnel openings only a little larger than the body diameter of an adult skink, were found to be suitable for skinks of all sizes, and were used successfully 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 routes. Each method of collecting skinks resulted in occasional mortality to them 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 occurred 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 exerting a slight pull on each end of the lizard until it tired and relaxed its muscles, eliminating bends and kinks. Even with such precaution, precise measurements could not be obtained and the readings often varied a millimeter or more for the same skink measured two or more times on the same day. Tail length was similarly recorded 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.

Continue reading Life History and Ecology of the Five-Lined Skink, Eumeces Fasciatus free in the Wunder reader →