Distress Vocalizations of Young in Two Subspecies of Peromyscus Maniculatus

Abstract

Vocalizations of young Peromyscus maniculatus bairdii and P. m. gracilis in an acute cold stress situation were studied by tape recording and spectrographic analysis. Vocalizations consisted of regularly patterned sequences of sounds; typically a series of two to five short pulses of 0.1 to 0.2 seconds' duration was separated by short pauses of 0.07 to 0.15 seconds, and each series of pulses was followed by a longer pause of 0.5 to 5.0 seconds. The series was then repeated. The dominant frequency of the pulses ranged from 3.6 to 26.5 kilocycles and usually showed an initial rise and terminal fall in frequency. Subspecific and age differences were found for several parameters of the vocalizations. The physiological basis and possible behavioral significance of the vocalizations are discussed.