Structural homologies and functional similarities exist between some vocalizations of the red panda and those of the giant panda, *Ailuropoda*, and Procyonidae.
The vocal repertoire of the red panda is small, but there is considerable variability within certain call types.
Tonal calls include an infant distress “wheet,” which may persist in the adult as a “squeal” under conditions of great duress, and a high-pitched, modulated-frequency “twitter” heard as a contact call in young and adults. A harsh, broad band, polysyllabic “quack-snort” is emitted by young and adults under conditions ranging from mild annoyance to intense aggression. Nonvocal sounds of communicatory function include exhalation of air through the nose and mouth, (puffing,) while raising and lowering the head during mild threat displays, and jaw-clapping while turning the head towards a nearby individual during a low intensity aggressive encounter. Grunts and snorts are also produced by animals engaged in wrestling or fighting.
Structural homologies and functional similarities were found between some vocalizations of the red panda and those of the giant panda, Ailuropoda, and Procyonidae.