The vocal repertoire of Tibetan macaques (Macaca thibetana): A quantitative classification.

Vocal repertoires are basic and essential components for describing vocal communication in animals. Studying the entire suite of vocal signals aids investigations on the variation of acoustic structure across social contexts, comparisons on the complexity of communication systems across taxa, and in exploration of the evolutionary origins of species-specific vocalizations. Here, we describe the vocal repertoire of the largest species in the macaque genus, Macaca thibetana. We extracted thirty acoustic parameters from call recordings. Post hoc validation through quantitative analyses of the a priori repertoire classified eleven call types: coo, squawk, squeal, noisy scream, growl, bark, compound squeak, leap coo, weeping, modulated tonal scream, and pant. In comparison to the rest of the genus, Tibetan macaques uttered a wider array of vocalizations in the context of copulations. Previous reports did not include modulated tonal screams and pants during harassment of copulatory dyads. Furthermore, in comparison to the rest of the genus, Tibetan macaque females emit acoustically distinct copulation calls. The vocal repertoire of Tibetan macaques contributes to the literature on the emergence of species-specific calls in the genus Macaca with potential insights from social, reproductive, and ecological comparisons across species. Am. J. Primatol. 78:937-949, 2016.