University of Kansas Publications, Museum of Natural History

University of Kansas Publications Museum of Natural History Vol. 19, No. 2, pp. 85-194, 48 figs., 4 pis. August 10, 1970 Ecological Study of the Worm Snake Carphophis vermis (Kennicott) BY DONALD R. CLARK, JR. University of Kansas Lawrence 1970 University of Kansas Publications, Museum of Natural History Editors of this number: Frank B. Cross, Henry S. Fitch Volume 19, No. 2, pp. 85-194, 48 figs., 4 pis. Published August 10, 1970 University of Kansas Lawrence, Kansas PRINTED BY (BOB) SANDERS. STATE PRINTER TOPEKA, KANSAS 1970 32-9080 Ecological Study of the Worm Snake Carphophis vermis (Kennicott) BY DONALD R. CLARK, JR.* CONTENTS PAGE Introduction 89 Acknowledgments 89 Materials and Methods 90 Study Areas 91 Morphology 94 Scutellation 94 Skull and Dentition 95 Coloration 96 Hemipenis 97 Maximum Size 98 Proportions 99 Sexual Dimorphism 100 Adaptation for Fossorial Habits among Worm Snakes 101 Distribution 104 Habftat 106 General 106 Amphibian and Reptile Associates 106 Size of Rock versus Snout-Vent Length 107 Levels of Soil Moisture 109 Soil Type Ill Temperature Relationships Ill AcTiYiTY Cycles 113 Seasonal 113 Daily 114 Burrowing Behavior 115 Movements 115 Reproduction 122 Sexual Maturity and Testicular Enlargement in Males 122 Sexual Maturity and the Ovarian Cycle in Females 128 Mating and Fertilization 132 Oviposition and the Clutch of Eggs 136 Incubation 150 Hatching and Hatchlings 155 * Present address Department of Wildlife Science, Texas A. and M. Uni- versity, College Station, Texas 77843. (87) University of Kansas Publs., Mus. Nat. Hist. PAGE Growth 158 Age and Snout-Vent Length 158 Age and Anomalies of Head Scutes 164 Age and Persistence of the Umbilical Scar 169 Age and Healing of Scale Clips 169 Ecdysis 170 Food Habits 172 Mortality Facttors and Defense 174 Climate 174 Predators 175 Parasites 176 Injuries 178 Defense and Escape 179 Population Density and Structure 180 Density 180 Sex Ratios 182 Age Structure 182 Summary 184 Literature Cited 190 INTRODUCTION Carphophis vermis (Kennicott) is a small, fossorial snake (PL 1, Fig. 1) which may be found in abundance during the spring be- neath large rocks along limestone outcrops in northeastern Kansas. In spite of the fact that populations of this species, or its eastern relative C. amoenus, are readily available over much of the eastern half of the United States, the ecology of Carphophis is almost completely unknown. During the warm months from September 1964 through October 1967, field studies of the worm snake based on mark and recapture methods were conducted in northeastern Kansas. When snakes were in hibernation, studies were concentrated on preserved specimens of both C. vermis and C. amoenus, and in late summer of 1965, several laboratory experiments were conducted with living snakes from local populations. Designation of C vermis as a full species in this report is based on earlier conclusions (Clark, 1968). The objectives of the study were to describe the ecology and life history of C. vermis and compare these with similar data for C. amoenus which are available in the literature or obtainable from preserved specimens. Hopefully this report will help clarify the ecology, evolution and structure of fossorial reptiles in general. Acknowledgments I am most grateful to Dr. Henry S. Fitch who provided the opportunity to make this study, gave it thoughtful guidance and supervision throughout, worked long hours beside me in the field on many occasions, and carefully criticized the manuscript. I also thank Drs. William E. Duellman, Frank B. Cross, and Daniel H. Janzen for critical readings of the manuscript, in a fonn submitted as a doctoral dissertation at the University of Kansas, in May 1968. Many persons have my appreciation for specimens contributed, but Robert R. Fleet deserves special thanks for numerous large series which materially aided the project. For specimens of Carphophis amoenus used in anatomical studies, I drank Drs. Richard Highton and Roger W. Barbour and Messrs. Neil D. Richmond, J. M. Jones, Herbert S. Harris, Jr. and Robert G. Tuck, Jr. For the loan of specimens in their care, I thank Dr. Duellman, Mr. Hymen Marx, Dr. James A. Peters, Dr. Phihp W. Smith, and Dr, Hobart M. Smith. For the use of their property as study areas, I am grateful to Mr. Fred A. Ramseyer and Mr. Theodore R. Wiggins. Special thanks are due to Dr. Walter J. Harman for identification of earth- worms from stomachs, Mr. W. Grant Inglis for identifying parasitic nematodes, and Mr. Jack L. Boese for identification of parasitic mites. Photographic assistance was given by Messrs. George L. Callison, Richard R. Shivers, Arthur C. Echtemacht, Charles W. Myers, and Dr. Fitch. Advice on statistical problems was provided by Mr. Edwin H. Bryant. Messrs. Wilfred T. Neill, Frank Groves and Roger Conant supplied information regarding distribution records of C. amoenus. (89) 90 University of Kansas Publs., Mus. Nat. Hist. Financial support from the National Science Foundation (G-17084, Henry S. Fitch, Principal Investigator) is gratefully acknowledged. Finally, for her unselfish encouragement and devotion throughout this study, I thank my wife, Judith. Materials and Methods Specimens of Carphophis vermis were collected at various sites in Douglas and the nearby counties of Jefferson, Leavenworth, Johnson, Franklin, Jack- son and Wyandotte in northeastern Kansas during the warm months (April through October) from September 1964 through October 1967. Data were recorded concerning sex, snout-vent length, tail length, weight, reproductive condition, parasites, wounds or scars, anomalies of scutellation, stomach contents, umbilical scar, and other incidential features. In April 1965, worm snakes were found to be abundant along a segment of hmestone outcrop on the Theodore R. Wiggins farm adjacent to the Uni- versity of Kansas Natural Histoiy Reservation and intensive study on this area began. Landmarks were established by numbering many of the larger trees and assigning names to certain large rocks. After examination and marking, each specimen was returned (usually the same day but occasionally on the following day) to the rock under which it had been found. If a snake had been caught and marked previously, the distance between the two capture points was measured in the field. Out of 153 worm snakes marked and re- leased on the Wiggins Area, 36 were recaptured a total of 50 times. On the Reservation, five of 87 specimens that were marked were each recaptured once. Beginning in April, 1966, all specimens collected on areas other than the Wiggins Area and Reservation were marked and introduced into a wooded hillside with limestone outcroppings on the Fred A. Ramseyer farm one-half mile north of the Reservation. Of 604 specimens introduced during 1966 and 1967, 88 were recaptured 104 times. Data concerning movements and growth of these intioduced snakes have been compared with similar data from resident individuals on the Wiggins Area and Reservation. On April 21, 1966, aerial photographs of the Wiggins and Ramseyer Areas were taken. Maps (Figs. 1 and 2) with a scale of two feet to one millimeter were made from these photographs and allowed accurate determination of distances between points of capture. Funnel traps (Pi. 1, Fig. 2) of a type previously described (Clark, 1966a) were used extensively on the Ramseyer Area and Reservation and on a small scale on the Wiggins Area. In 1965, six traps were operated at three stations on the Wiggins Area from July through October and concurrently 47 traps were maintained at 25 stations on the Reservation. Throughout the 1966 season, ten traps were used at seven locations on the Wiggins Area, 20 traps were placed at 20 stations on the Ramseyer Area and 73 traps were operated at 39 locations on the Reservation. During the 1967 season, trapping was discontinued on the Wiggins Area while 38 traps were used at 38 stations on the Ramseyer Area and 85 traps were operated at 44 stations on the Reservation. Traps yielded totals of nine captures on the Wiggins Area, 55 captures on the Ramseyer Area, and 26 captures on the Reservation. Worm snakes have decreased in number on the Reservation since grazing was discontinued in 1948 (Fitch, pers. com.) and numbers sufficient for intensive study are no longer present. Trapping there was directed principally toward Ecological Study of the Worm Snake 91 the abundant ringneck snake (Diadophis punctatus) in connection with other studies. Traps were used primarily with drift fences on the Reservation, but on the Wiggins and Ramseyer Areas most were set adjacent to large rocks where snakes were intercepted as they travelled along them. Marking was done by using small scissors to excise portions of one posterior ventral scute and two subcaudal scutes on each specimen. Details of the method were given by Fitch ( 1963a: 360-361). If part of a scale or scales in the first row of dorsals was removed along with the lateral end of the ventral or subcaudal, the mark remained obvious because one continuous scale formed in the excised area thereby altering the normal pattern of sutures. If only one scute, or part of one, was removed, the completely regenerated dermis and epidermis were occasionally quite similar to that before marking. Preserved worm snakes examined in detail included 279 C. vermis from the University of Kansas Museum of Natural History, and 202 C. amoenus from the United States National Museum, Field Museum of Natural History, University of Illinois Museum of Natural History, Illinois Natural History Survey, and the University of Kansas Museum of Natural Historj'. Standard scale counts and measurements were taken from these specimens as well as measurements of head width and eye diameter and notation of the presence or absence of anal ridges. Internally, lengths of testes or ovarian or oviducal follicles were measured, presence or absence of spermatozoa in the vasa deferentia or oviducts was noted, and undigested stomach contents were removed for later study.

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