Investigating personality in vipers: individual rattlesnakes exhibit consistent behavioral responses in defensive and exploratory contexts

A burgeoning literature in animal behavior has demonstrated that most animals exhibit consistent individual variation in core behavioral traits or personality. However, the taxonomic spread of animal personality studies is uneven, with some ecologically important and diverse taxa still unstudied. Some of these understudied groups, such as venomous snakes, are also frequent targets of mitigation due to human-wildlife conflict, and conservation researchers have been increasingly focused on developing a general understanding of how individual personality, or temperament, mediates wildlife responses to management or mitigation actions. In this study, we used 20 captive Western Rattlesnakes (Crotalus oreganus) in standardized assays to test for repeatable behaviors (i.e., personalities) between individuals and examine possible relationships in personality traits across contexts (i.e., behavioral syndromes). Repeatability of behaviors was assessed over five repeated trials consisting of a handling assay, an open field test, and a threat assay. We found several behaviors related to exploration/avoidance, activity level, and boldness/shyness showed significant repeatability. However, we found no evidence for behavioral syndromes across contexts. Our analysis shows that, similar to many other species and taxonomic groups, viperid snakes also display individual personality traits when tested under standardized conditions, and we discuss the implications of this finding for mitigation, conservation, and comparative analyses across broadly similar species groups. Significance Statement It has now been well established that non-human animals exhibit individual behavioral traits similar to what humans term personality, and animal personality studies are becoming more important in the field of conservation and management. However, there are no previous personality/behavioral studies on venomous snakes, which are not only important predators in many ecosystems, but also a major source of human-wildlife conflict. We used a series of standardized behavioral tests to determine whether individual Western Rattlesnakes showed distinct personalities. We found that individual snakes did indeed exhibit repeatable behavioral traits consistent with personalities, but we did not find that these temperament traits were correlated across contexts. Our findings are important to developing a more nuanced view of the behaviors of venomous snakes and could aid in the development of more humane strategies to reduce human-wildlife conflict.

Automated summary

A growing body of research in animal behavior has shown that most animals exhibit consistent individual variation in core behavioral traits or personality. However, there are still some ecologically important and diverse taxa, such as venomous snakes, that have not been studied in terms of animal personality. In this study, we tested 20 captive Western Rattlesnakes to determine if they exhibited repeatable behaviors (personalities) and if there were relationships between personality traits across different contexts (behavioral syndromes). We found that behaviors related to exploration/avoidance, activity level, and boldness/shyness showed significant repeatability. However, we did not find evidence for behavioral syndromes across contexts. Our findings contribute to a better understanding of the behaviors of venomous snakes and may help develop more humane strategies to reduce human-wildlife conflict.