Polymorphic Clay Models of Thamnophis Sirtalis Suggest Patterns of Avian Predation

Abstract

Models of snakes varying in color pattern have been used to test hypotheses about predation and mimicry. In the present study, clay models of the common garter snake were used to test for a difference in attack frequency between adult and juvenile striped and melanistic garter snakes; such difference may indicate a difference in cryptic coloration between the two morphs. The research was performed on the shores of Sandusky Bay and Lake Erie, where polymorphic garter snake populations contain both striped and melanistic garter snakes. There was no difference in attack frequency between the two morphs; however, juvenile snake models were attacked more frequently than adult ones. The study suggests that melanism may not confer a strong disadvantage with respect to visually-oriented predators.