Aggregation and social interaction in garter snakes (Thamnophis sirtalis sirtalis)

Abstract

Previous research has shown that competition, familiarity, diet, and relatedness can all influence aggregation patterns in garter snakes. We controlled for these factors and examined social aggregation patterns in juvenile Eastern garter snakes (Thamnophis sirtalis sirtalis). We assayed snakes individually for consistent individual differences in boldness and sociability. We then placed snakes in groups of 10 in an enclosure with four shelters and observed their social interactions over a period of 8 days. We demonstrate that the snakes actively seek social interaction, prefer to remain with larger aggregates, and associate nonrandomly with specific individuals or groups. We show that their social interaction patterns are influenced by individual boldness, sociability, and age. The snakes’ social networks were perturbed twice a day by “shuffling” their locations. Despite these disturbances, the snakes eventually re-formed their preferred social environment. Aggregation and exploration patterns also varied across time, with most activity occurring later in the day. These results highlight the complexity of snake sociality and may have important implications for conservation efforts. Snakes are often considered nonsocial animals, but this is inaccurate. We used social network analyses to compare juvenile Eastern garter snakes’ group behaviors to their individual personalities. Our research demonstrates that these snakes actively seek out social interaction and prefer to join and remain with larger groups and that their social interaction patterns are influenced by consistent individual differences in boldness and sociability. Our work contributes to a sparse but growing body of literature on sociability in reptiles. This work is important for changing perceptions among the scientific community and the public as a whole. As a consequence, it may aid efforts in developing appropriate conservation techniques that consider sociability patterns in relocated reptiles.