Chimpanzee vocalisations and social bonding

Our closest living relatives, chimpanzees, live in complex fission-fusion societies that are characterised by the presence of strong social bonds, particularly between males. Alliances between males are vital for achievement of high status and males engage in a range of social bonding behaviours, including grooming, meat sharing and coalitionary support in fights. I will present data from wild chimpanzees that highlights the potential role of vocalisations in social bonding and indicates vocalisations are directed at specific individuals, rather than being indiscriminately or reflexively produced.  More specifically, I will show, through observational and experimental work, that chimpanzee food-associated calls are not an automatic reflexive reaction to food, but communicative signals directed at important social partners. These signals help keep important social partners in close proximity, which facilitates the occurrence of further bonding behaviours. I will then explore the potential of pant hoot chorus displays to signal short term bonds between males. I show that in the short term pant hoot choruses are a more reliable predictor of other affiliative, bonding behaviour between a dyad, than grooming. I conclude that vocalisations may play an important role in establishing and maintaining social bonds between male chimpanzees.