The vocal repertoire of infant giant pandas (Ailuropoda melanoleuca)

Infant giant pandas (Ailuropoda melanoleuca) are highly vocal during the first few weeks of their life. Despite this, no previous studies have attempted to systematically categorize infant giant panda vocalizations into different call types. In this study, we used acoustic and video analyses to split infant giant panda vocalizations into three distinct call types based on their acoustic structure as well as their use in different behavioural contexts. A discriminant functions analysis on the acoustic variables confirmed our initial subjective classification of 281 vocalizations into three call types: the harsh sounding “squawk”, the high-pitched “squall” and the pulsed “croak”. Based on the observed spectral acoustic characteristics, none of these three infant call types appears to be a precursor of an adult giant panda vocalization. In addition, individual call types could not be assigned to specific recording contexts. These findings suggest that infant giant panda vocalizations convey information about a cub's distress and need, rather than being tied to specific contexts of emission. Our objective demonstration that infant giant pandas have three basic call types provides a foundation for future studies of vocal ontogeny in this highly endangered species.