Abstract

Many studies indicate that various vertebrates and invertebrates use sensory cues to recognize predators and to evaluate predation risk. Lizards and birds frequently occupy the same habitats; consequently, avian predation on lizards has been implicated as an important selective pressure on lizard behavior. However, there are few studies on how lizards respond to nonvisual cues. The response of adult male Brown Anoles (Anolis sagrei) to calls of birds was studied to determine whether they use auditory cues as an indicator of predation risk from birds. Anoles responded significantly more often with head tilt (increased vigilance) during playback of predatory vocalizations (Kestrel and Red-tailed Hawk calls) compared with low-risk stimuli (nonpredatory bird calls and white noise). Responses to auditory cues suggest that male Brown Anoles are able to distinguish the calls of birds known to prey upon lizards from the calls of nonpredatory birds. More important, this study demonstrates that anoles, most of which are nonvocal, are able to obtain information about predation risk through the use of auditory cues and that the role of hearing in these lizards has been underappreciated.