Conspecific trailing behaviour of red-sided garter snakes, Thamnophis sirtalis parietalis, in the natural environment

The ability of animals to orient based on pheromonal cues in the environment can have significant consequences to their reproductive success and survival. For example, it is hypothesized that snakes use pheromone trails to locate potential mates during the breeding season and to locate winter hibernacula. Numerous studies have demonstrated that snakes are capable of detecting and following pheromone trails in the laboratory, but it has yet to be shown experimentally whether snakes use such behaviour in their natural environment. In this study, we conducted trailing experiments to test the response of adult red-sided garter snakes to pheromone trails on the natural substrate under naturally occurring conditions during two periods, the spring breeding season and the autumn migration back to the hibernacula. Male snakes detected and followed female trails in the spring, while neither sex displayed trailing behaviour during the period of autumn migration. Our results suggest that adult garter snakes use pheromone trails for locating potential mates during the breeding season and most likely rely on other mechanisms (e.g. visual cues) for navigation to overwintering hibernacula.