Heterospecific alarm call recognition in a non-vocal reptile

The ability to recognize and respond to the alarm calls of heterospecifics has previously been described only in species with vocal communication. Here we provide evidence that a non-vocal reptile, the Galapagos marine iguana ( Amblyrhynchus cristatus), can eavesdrop on the alarm call of the Gala pagos mockingbird ( Nesomimus parvulus) and respond with anti-predator behaviour. Eavesdropping on complex heterospecific communications demonstrates a remarkable degree of auditory discrimination in a non-vocal species.