Researchers, including those from Max Planck Institute for Evolutionary Anthropology, Germany, investigated the signalling function of social odours in non-human great apes. Two groups of chimpanzees were presented with urine from group members, strangers and an unscented control in aerated plexiglass boxes and their behaviour was videotaped.
The study published in the Proceedings of the Royal Society B journal found that chimpanzees sniffed longer at urine than at the control, suggesting they perceive the odour of other chimpanzees.
More importantly, they discriminated between the smell of group members and strangers, sniffing outgroup odours longer than ingroup odours.
“Chimpanzees are highly territorial, and encounters between groups are mostly hostile — in fact, they sometimes kill individuals from other communities — so olfactory cues might help them to locate other animals and determine whether they are group members or strangers, enhancing their survival and leading to fitness benefits,” says Stefanie Henkel of the University of Leipzig.
“Odour might be especially important because most chimpanzees live in dense forests where visibility is low, and because in chimpanzee societies, group members split up into subgroups that may not see each other for days,” Henkel says.
The researchers found that chimpanzees sniffed longer at the odour of the more closely related odour-donor, providing the first evidence for odour-mediated kin recognition in non-human great apes.
“Our results help us to understand the evolution of primate chemical communication and suggest that we should pay more attention to olfaction in apes,” says Setchell. PTI