Developmental changes in ultrasonic vocalizations by infant Japanese echolocating bats, Pipistrellus abramus

摘要

Developmental changes in vocalizations by Pipistrellus abramus were investigated during the first post-natal month. Vocalizations by pups on the day of birth were frequency-modulated ultrasounds from 30.0 4.0 kHz to 19.3 1.9 kHz with multiple harmonics. The terminal frequency of the second harmonic (TF _2) of pup vocalizations corresponded to that of the fundamental (TF_1) in adult bats (41.4 2.6 kHz), suggesting that pup vocalizations can be easily detected by the mother. In addition, there are two types of infant vocalization: short duration echolocation precursor and long duration isolation calls, which showed separate developmental patterns over time.