Agonistic Screams in Wild Chimpanzees (Pan troglodytes schweinfurthii) Vary as a Function of Social Role.

Abstract

Some nonhuman primates have demonstrated the capacity to communicate about external objects or events, suggesting primate vocalizations can function as referential signals. However, there is little convincing evidence for functionally referential communication in any great ape species. Here, the authors demonstrate that wild chimpanzees (Pan troglodytes schweinfurthii) of Budongo forest, Uganda, give acoustically distinct screams during agonistic interactions depending on the role they play in a conflict. The authors analyzed the acoustic structure of screams of 14 individuals, in the role of both aggressor and victim. The authors found consistent differences in the acoustic structure of the screams, across individuals, depending on the social role the individual played during the conflict. The authors propose that these 2 distinct scream variants, produced by victims and aggressors during agonistic interactions, may be promising candidates for functioning as referential signals.