Avoidance responses to scents of snakes that pose different risks of predation by adult natterjack toads, Bufo calamita

Abstract

Many antipredator behaviors are mediated by the ability of prey to recognize chemical cues from predators. Adult amphibians mainly use vision to detect predators, but the ability to detect chemicals of predators and conspecifics could be advantageous, especially when assessing safety of potential refuges where the use of visual cues is limited. We analyzed in the laboratory whether refuge choice by adult natterjack toads ( Bufo calamita Laurenti, 1768) was influenced by the presence in the refuge of chemical cues from conspecifics or from two different snake predators ( Natrix maura (L., 1758) and Natrix natrix (L., 1758)). Natterjack toads avoided refuges scented by snakes and spent less time in refuges with snake scent than in refuges with conspecific scent. Toads also seemed to have different hiding behaviors depending on the snake species that they found. We concluded that adult natterjack toads were able to recognize and avoid chemical cues of dangerous snakes, but it was not clear whether toads discriminated between chemicals of the two snake species, even though these two snakes might pose different risks of predation.