Chimpanzees differentially produce novel vocalizations to capture the attention of a human

Chimpanzees, Pan troglodytes, produce numerous species-atypical signals when raised in captivity. We examined contextual elements of the use of two of these vocal signals, the 'raspberry' and the extended grunt. Our results demonstrate that these vocalizations are not elicited by the presence of food, but instead function as attention-getting signals. These findings reveal a heretofore underappreciated category of animal signals: attention-getting sounds produced in novel environmental circumstances. The invention and use of species-atypical signals, considered in relation to group differences in signalling repertoires in apes in their natural habitats, may index a generative capacity in these hominoid species without obvious corollary in other primate species.