Ecological Observations on Graham's Watersnake (Regina grahami Baird and Girard)

摘要: A study of various aspects the ecology watersnake, Regina grahami, has clarified some its biological relationships. Crayfish are principal food for this prairie species and taken when thick exoskeleton been softened by molt. Rarely, in absence crayfish, vertebrate prey is taken. Movements frequent, but undetermined magnitude. Activity continues from April to October chiefly nocturnal. The sex ratio 1: 1. Age-size groups discernible until second spring, become obscured subsequently as growth slows. viviparous mean number young per reproductive female approximately 15. INTRODUCTION Graham's watersnake seems moderately abundant permanent bodies water throughout most range represented numerous specimens several museum collections. Nevertheless there few literature records regarding species. Most general accounts based on Strecker's (1926) semi-popular discussion. remaining fragmentary. From compilation such information my original data, significant trends revealed. Interest stimulated suggestion Smith Huheey (1960) that three similar constitute a genus (Regina) distinct more typical watersnakes (Natrix). METHODS Live-trapping snakes was carried Kansas season activity 1965. Captured were measured, weighed, marked, sexed released. Traps used to, those described Fitch (1951). Snakes marked clipping subcaudal scales. Much obtained examination preserved University Museum Natural History, collection Illinois History Survey History. Smaller series examined private Preserved digestive tracts routinely examined. OBSERVATIONS AND DISCUSSION