Observations on the Life Cycles of Painted Turtles (Genus Chrysemys)

Abstract

The members of the Genus Chrysemys provide excellent material for the study of the comparative life histories of turtles. The four subspecies occupy an area that includes the greater part of continental United States and Canada north to 510 N. Latitude. The limits of distribution of the three northern forms are well defined but the eastern and western limits of the range of Chrysemys picta dorsalis (Agassiz) are not known. The differences in area of the ranges of the four forms is striking. Chrysemys picta belli (Gray) occurs from Washington and Oregon on the West southeastward to northern Mexico and northeastward to Missouri and Illinois and to 510 N. Latitude. Chrysemys picta marginata (Agassiz) occurs from the southern part of Ontario southwest through Michigan, eastern Illinois to northern Tennessee and northeastward to Pennsylvania, thence north through New York and extreme western Quebec to 510 N. Latitude. Chrysemys picta picta (Schneider) occurs from Quebec, Nova Scotia and New Brunswick southward through Maine, Vermont and New Hampshire along the Atlantic Coast to Florida. Chrysemys picta dorsalis (Agassiz) occupies the Gulf Coast plain from extreme southern Illinois south to the Gulf. The westward and eastward limits of its range are poorly defined, but the form apparently does not occur in eastern Kentucky, Tennessee or Alabama or western Missouri, Arkansas or eastern Texas. A population in southern Alabama and western Florida may represent a fifth subspecies. Intermediates between each form occur at the junctures of the ranges. Individuals intermediate between Chrysemys picta belli and Chrysemys picta marginata are found in a zone about 200 miles in width extending from southern Illinois north to Ontario. The valley of the Hudson River and the areas of Massachusetts, Rhode Island, Connecticut, Delaware, eastern Pennsylvania and Maryland support a population intermediate between C. picta marginata and C. picta picta. A population that reflects the characters of C. picta bell, C. picta marginata and C. picta dorsalis occurs in extreme southern Illinois. A program of research was undertaken in 1937 aimed at exploring possible ecological differences between populations occurring in northern Michigan, southern Illinois and Tennessee. The studies have since been extended to the Gulf Coast. The bulk of our knowledge of these turtles is contained in short notes, brief discussions in regional reports and the work of experimental biologists. There have been no intensive studies of the bionomics of any one group. Acknowledgement.-I am indebted to many present and former students for their enthusiastic participation in field work. Particularly valuable have been the contributions of Mr. Philip Smith, Mr. Lendell Cockrum, Mr. A. H. Chaney and Mr. Leslie Ellis. A series of turtles essential to the evaluation of growth determinations was loaned by Dr. Norman Hartweg of the Museum of Zoology, University of Michigan. Habitat.-These turtles generally occupy static waters such as lake borders, ponds, and quiet creeks. They are but rarely found in streams with current