Species and sex differences in the screams of chim

Authors: John C Mitani Julie GrosLouis

Publish Date: 1995/06/01

Volume: 16, Issue: 3, Pages: 393-411

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Abstract

We examined screams of chimpanzees and bonobos to investigate interspecific and intraspecific variability in call structure Measurement of 11 acoustic features of screams revealed differences between and within species Oneway analyses of variance and discriminant function analyses show that the calls of chimpanzees and bonobos differ primarily in spectral characteristics Spectral features also account for acoustic differences between the sexes These acoustic variations may be attributable to differences in body size and social dispersion between the two species and sexes The effectiveness with which an acoustic feature could be used to discriminate the two species and female bonobos from male bonobos is negatively associated with its relative variability These data are consistent with the hypothesis that optimal signals for group identification vary little within groups but differ widely between groups

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