Do individual differences in behavior influence wild rodents more than predation risk?

Abstract

Prey can enhance their survival by eliciting an appropriate response to predators. Theoretically, prey should distinguish odors of predators and nonpredators. The manifestation of defensive antipredator behaviors has been extensively researched in domestic species (i.e., the relationship between laboratory-bred rats and domestic cats). However, little is known about the expression of these behaviors in wild rodents. Studies have so far focused on quantitative assessments of cost–benefit trade-offs or giving-up densities. We examined the expression of fine-scale defensive behaviors in Arnhem rock rats (Zyzomys maini) in response to fecal cues from 2 predators (the northern quoll [Dasyurus hallucatus] and the dingo [Canis dingo]), a nonpredator (the short-eared rock-wallaby [Petrogale brachyotis]), and a control (water). We adapted a predator-odor avoidance apparatus that has been widely used for domestic rodent studies to film the behavior of wild rock rats in a captive environment. Rock rats did not alter their behavior in the presence of odors of nonpredators, predators, or controls. In the current study, individual rock rats behaved in a consistent manner across time, and we identified 3 individually consistent behaviors which may suggest the existence of personality traits in this species. We suggest that these individual differences may influence wild rock rat behavior more than predation risk. These differences should therefore be taken into consideration when investigating behavioral responses to predators in wild populations.