The development of alarm call behaviour in mammals and birds

Alarm calling is a widespread antipredator behaviour. Although the function and evolution of alarm call behaviour have long been studied in detail, only in the last decade has there been an upsurge in research into its development. Here, we review the literature on the development of alarm call production (the delivery of calls with a specific set of acoustic features), alarm call usage (the use of calls in particular contexts) and alarm call responses (the responses to calls produced by others). We detail the mechanistic processes that may underlie the development of each aspect, consider the selection pressures most likely to explain the relative importance of these processes, and discuss the substantial variation in developmental rates found both between and within species. Throughout, we interpret existing findings about age-related differences in alarm call behaviour from two major communicatory viewpoints: the idea that signals carry information from sender to receiver, with young taking time to acquire adult-like skills; and the possibility that signals are used to manage the behaviour of receivers, with young behaving adaptively for their age. We conclude that a broader use of various techniques (e.g. cross-fostering and temporary removals), the formation of stronger collaborative links with other disciplines (e.g. physiology and neurobiology) and the initiation of new research avenues (e.g. kleptoparasitism) will ensure that studies on the development of alarm call behaviour continue to enhance our understanding of such topics as the evolution of communication and language, kin selection and cognitive processing.