Dissimilarities in behavioral responses of snakes to roads and vehicles have implications for differential impacts across species
Roads can act as a barrier to overland movement of animals by causing habitat fragmentation, disrupting landscape permeability, and having an impact on survivorship patterns and behavior. We conducted field experiments to determine how southeastern U.S. snake species with different behaviors and ecologies responded to roads. We attributed interspecific differences in how individual snakes responded to ecological and behavioral differences among the species tested. The probability that a snake would avoid entering the road rather than crossing it varied significantly among species. Smaller species showed high road avoidance behavior. We also observed significant differences in crossing speeds among species. Most nonvenomous species crossed more rapidly than venomous ones. Nonetheless, all species minimized road-crossing time by traveling at perpendicular angles. We also conducted field tests to determine how individual snakes respond to passing vehicles. We observed that most individuals of the three species tested became immobile when a vehicle passed, a non-adaptive behavior that would prolong roadcrossing time of an individual and further exacerbate a species’ vulnerability when crossing roads. It is essential that the differential responses of snakes and other animals to roads be identified if the direct impacts of road mortality are to be incorporated into future mitigation plans that minimize road impacts in efforts to design more effective transportation systems.