Behaviour 2019
Motherese in bats: female pup-directed vocalizations in Saccopteryx bilineata
Ahana A. Fernandez1,2, Mirjam Knörnschild1,2,3. 1Animal Behavior Laboratory, Free University of Berlin, Berlin, Berlin, Germany; 2Museum für Naturkunde - Leibniz Institute for Evolution and Biodiversity Science, Berlin, Berlin, Germany; 3Smithsonian Tropical Research Institute, Panama City, Panama, Panama

Social feedback is important during human language development and in the vocal ontogeny of many non-human animals. Infant-directed speech – or motherese –  is a special form of vocal social feedback in humans, facilitating language acquisition and learning. Motherese is characterized by high pitch, expanded intonation contours, and slower speech tempo. Moreover, the vocal timbre (i.e. “color” of voice) of motherese differs from the timbre of speech directed at adults. In animals, pup-directed vocalizations are very common, however, so far there is hardly any research on whether there is a similar phenomenon as motherese in animal vocalizations. The greater sac-winged bat, Saccopteryx bilineata, is a vocal production learner with a large vocal repertoire, which is acquired through a conspicuous babbling phase during ontogeny. We compared acoustic features between female pup-directed and adult-directed vocalizations and demonstrated that they differed in timbre and peak frequency. Our findings indicate, that parent-offspring communication in bats is more complex than previously thought, with female pup-directed vocalizations reminiscent of human motherese.