Individuality and male discrimination of female copulation calls in the yellow baboon

In a wide variety of animal species, females produce vocalizations just before, during or immediately after copulation. These calls are thought to be sexually selected traits that function to incite males to compete for access to the calling females in such a way that, by calling, females maximize the quality and/or the number of their mating partners. The signalling of individual identity within these vocalizations, in conjunction with male discrimination between females on this basis, would have important implications for their function. I analysed the copulation calls of free-ranging yellow baboons, Papio cynocephalus cynocephalus, to examine whether sufficient acoustic cues existed to broadcast information on the individual identity of the caller. Discriminant function analysis indicated that calls could be assigned to the correct female with a high degree of accuracy, both when considering calls given throughout the menstrual cycle and also those given only during the period of likely conception (when the sexual swelling is at its largest). A playback experiment showed that consorting male baboons were able to discriminate the copulation call of their consort female from that of another cycling female. I discuss the implications of individuality of female copulation calls and males’ perception of this variability.