The Effects of Temperature and Body Size on Strike Performance in Rattlesnakes

Whitford, Malachi

mwhitford@ucdavis.edu

Freymiller, Grace A Department of Biology

San Diego State University

San Diego, California, USA

Higham, Timothy E.

Department of Evolution, Ecology, and Organismal Biology University of California - Riverside Riverside, California, USA

Clark, Rulon W. Department of Biology

San Diego State University

San Diego, California, USA

Predator-prey interactions are major selective forces, and their outcome is responsible for shaping adaptations within organisms and structuring communities. Most interactions are dynamic and interactive across several discrete stages (e.g., searching, evaluation, attack, subjugation, consumption), and the behaviors of both parties can alter the outcome at any given stage. For many systems, the factors that affect the final outcome of the interaction are not well understood because it is logistically difficult to quantify details of the behavior of both predator and prey in concert. We used a tractable field system to study interactions between a specialized ambush predator (Sidewinder, Crotalus cerastes) and one of its primary prey items (Desert Kangaroo Rat, Dipodomys deserti) to determine how dynamic behaviors at multiple stages influence the outcome. Because these interactions involve an ectothermic predator and endothermic prey, our current and future work is attempting to understand how the asymmetric effects of temperature on ectotherms versus endotherms may lead to changes in the outcome of predator-prey interactions. By examining the kinematics of a large sample of rattlesnake strikes under various temperature treatments, both in the field and the lab, we hope to provide insight into whether higher environmental temperatures and larger body size are associated with increased strike performance in Crotalus spp.