The Ontogeny of Vocal Communication in the Pika

Abstract

Vocalizations and behavioral data were obtained from a captive population of young pikas during social interactions with littermates and the mother. Pikas are capable of producing a graded series of three calls at birth which are associated with conditions of hunger, cold, injury, and other forms of physical discomfort. These vocalizations disappear around the time that weaning occurs and pikas become independent. The infant wail and twitter (which appear after the first week) undergo some structural modification as the young mature and become two vocalizations of the adult repertoire. Other vocalizations, the short call, long call, and panic call, which appear from the second through the fifth week, are structurally identical to future adult calls, although in some instances they are used in different situations. While there is an increase in the number of calls in the vocal repertoire as pikas mature, the most distinct ontogenetic shift in pika vocal communication concerns function.