Vocal Learning in Mammals
This chapter surveys the occurrence of vocal learning in mammals and discusses the possible reasons it has evolved. Although many birds are capable of vocal learning, unequivocal evidence for it is rare in mammals. The most versatile mammalian vocal learners are cetaceans, harbor seals, and humans, all of which are able to imitate new sounds. Greater horseshoe bats learn the main frequency of their echolocation calls from their mothers and are the only other mammals shown so far to be capable of learning to change frequency parameters in their calls. Nonhuman primates have been conditioned to alter the duration and amplitude of their calls but not their frequency parameters. It has been suggested that sexual selection, defense of resources, and individual recognition are the most likely reasons why vocal learning has evolved in mammals.