Scents and Scent Ability: Can Snakes Identify Heterospecifics and Conspecifics Using Airborne Semiochemicals?

All animals produce semiochemicals (i.e., scent)-chemical cues that elicit physiological or behavioral responses in other individuals. Scent detection and discrimination is a fundamental aspect of the social system of many animal species, and is particularly important for snakes and other squamate reptiles. Snakes rely extensively on chemosensory information in most aspects of their life, and have a highly derived tongue-vomeronasal sensory system that is active when exploring novel chemical cues. While the role of non-volatile semiochemicals in snake behavior has received a great deal of attention, measuring how volatile, airborne semiochemicals influence behavior has been understudied due to methodological hurdles. To explore this knowledge gap, we developed a novel bioassay to test the ability of snakes to discriminate among airborne semiochemicals from other individuals. Initial experiments using this bioassay demonstrate that prairie rattlesnakes (Crotalus viridis) can use airborne semiochemicals to discriminate between conspecifics and heterospecifics (gopher snakes, Pituophis catenifer), but not between different conspecific individuals. We discuss the further implications of these findings, highlighting the utility of our experimental approach for addressing future questions related to the relationships between semiochemical production, perception, and social behavior.