Ontogeny of Vocal Signals in the Big Brown Bat, Eptesicus Fuscus

Abstract

The production of vocal signals by infant bats is important for communication and may play a role in the development of sonar signals used for echolocation. Recordings of infant vocalizations from a variety of species show many similarities, even across different families of bats (e.g. Brown, 1976; Gould, 1971, 1975a, 1979; Matsumura, 1979; Brown and Grinnell, 1980; Brown, Brown and Grinnell, 1983). Young infant bats often emit multiple-harmonic sounds that are lower in frequency than the sounds of conspecific adults. In many species, the infant vocal repertoire includes sounds with relatively constant frequency components which are typically identified as isolation sounds. These sounds often promote approach and retrieval of an infant by its mother (e.g. Davis, Barbour and Hassell, 1968; Gould, 1971, 1975a; Brown, 1976; Thomson, Fenton, and Barclay, 1985).