Antipredation behavior covaries with body size in Neotropical snakes

The use of defensive behaviors to avoid predation increases the likelihood of survival. Snake species have evolved numerous and diverse antipredatory behaviors to fit a variety of natural histories. Understanding how snakes react to simulated predation events can help us understand their ecology. I conducted behavioral trials on 11 colubrid and dipsadid species (n = 16 individuals) in the Republic of Panama to examine patterns of antipredation behavior. The level of aggression and number of antipredatory behaviors exhibited during simulated predation was positively correlated with body size. To complement these results, data from previously published studies were used to assess these patterns with a larger sample of Neotropical colubrids and dipsadids (n = 44 species). Indeed, the level of aggression and number of antipredatory behaviors known for each species was positively correlated with body size. However, the positive association between the number of antipredatory behaviors known for a species and body size was driven largely by colubrids and not dipsadids. Larger snakes may be more intimidating to potential predators, therefore making aggressive defensive behaviors more likely to be successful. Larger snakes also may encounter a higher diversity of predators and may benefit from the ability to choose from a suite of defensive behaviors specific to certain contexts. Although this study suggests two interesting patterns in the defensive behaviors of Neotropical colubrids and dipsadids, comparative studies of the interactions between snakes and their predators are needed to better understand the pressures driving variation in snake antipredation behavior.