Behavioral responses to snake cues by three species of N eotropical rodents

Abstract

The ability to assess and avoid predation risk is thought to be a major determinant of behavior for small mammals. We assessed the antipredator responses of three Neotropical rodent species (Heteromys desmarestianus, Peromyscus mexicanus and Melanomys caliginosus) to cues (feces or actual presence) of the snake Bothrops asper. We investigated whether rodents avoided entering or spent less time in snake-cued areas using an experimental arena, and whether rodents reduced foraging efforts (measured by giving-up density) in snake-cued areas under laboratory, semi-natural and field conditions. P. mexicanus and M. caliginosus did not demonstrate any snake avoidance, and did not reduce foraging efforts under any conditions. H. desmarestianus significantly avoided live snakes only at very short distances (<20 cm), and reduced foraging efforts in the presence of snakes only under certain experimental conditions. These results are in contrast to many studies demonstrating antipredator behavior by small mammals in temperate and desert ecosystems in response to cues of predators, including snakes, and were influenced by overall low statistical power. This discrepancy may also be explained by the complexity of tropical forest systems, as rodents must assess a myriad of sensory cues and balance risk from multiple predator groups that require different avoidance strategies. An ambush-hunting snake such as B. asper may also face strong selective pressure to avoid detection by its mammalian prey.