Kanyawara chimpanzees are the focus of a new study on vocal behavior by Pawel Fedurek and colleagues. In many animals, such as pair-living birds and some primates, duetting or chorusing is believed to promote strong social bonds between calling individuals. Fedurek’s fieldwork at Kanyawara shows that such joint vocal displays might also play a bonding role in chimpanzees. The study examined the production of pant hoots – long-distance calls commonly given by chimpanzees. Since males often pant hoot together with other males, the researchers tested the idea that such chorusing reflects strong social bonds between males.
The results of the study supported this hypothesis. For example, a male was more likely to join in another male’s pant hoot if the calling male was his long-term friend. For chimpanzee males, maintaining bonds with other males is critical for obtaining social status and its associated benefits. This study shows that pant hoot chorusing might play an important role in such bonding.
However, the study also suggests that chimpanzee chorusing signals short-term affiliation between males, regardless of their long-term relationships. For example, male dyads, both friends and non-friends, were more likely to groom, or support each other in conflicts, on days when they chorused. Since chimpanzees form temporary sub-groups in which friends are not always present, forming short-term coalitions with available males may be beneficial. The authors suggest that pant hoot choruses facilitate the formation of such relationships in these complex societies.