Choices of Neonate Thamnophis elegans vagrans between Conspecific, Congeneric, and Heterogeneric Odors

Responses of snakes to pheromones of other conspecific individuals or of heterospecifics vary among species. Most colubrid snakes choose substrates marked by conspecifics over those marked by heterospecifics and over "clean" (unmarked) substrates. In such cases, snakes presumably are using chemical signals from other individuals as clues about suitable habital. In this study, neonate Thamnophis elegans vagrans were tested in a series of two-choice shelter tests to examine their reactions to odors of conspecifics, T. sirtalis (a congeneric), Charina bottae (a heterogeneric), and an unmarked control. In addition, we tested whether or not neonate T. elegans would discriminate between conspecific neonates and adults. Based on previous studies, we predicted that the snakes would choose conspecifics over heterospecifics and over unmarked substrates, and that there would be no difference in reactions to conspecific adults and neonates. However, the snakes chose the other odors over the conspecific odor, and generally chose the odor of another neonate over that of an adult T. elegans. It is possible that neonates avoid conspecific odors, especially adult odors, because larger T. elegans may eat smaller snakes and thus pose a threat of predation.