Coordination of joint activities and communication in wild chimpanzees (Pan troglodytes) of the Budongo Forest, Uganda
Abstract
Evidence from captive studies suggests that chimpanzees (Pan troglodytes) lack the
motivation to complete cooperative tasks and there is little evidence for communication
that coordinates their behaviour during joint actions or whether individuals have a
shared motivation towards the same goal. Two types of behaviour where individuals are
argued to engage in joint activity are investigated in the Sonso community of wild
chimpanzees in Budongo Forest Reserve, Uganda: joint travel and group hunting. This
study presents evidence from naturalistic observations, and also a playback experiment
to further investigate hunting behaviour. Joint travel appears to have no coordinating
signal or behaviour on a local level, although the use of pant-hoot vocalisations to
coordinate long-distance group travel is supported. In group hunting, bark vocalisations
are associated with initiating a group hunt, indicating their potential role in coordination
of joint action. Bark production also appears to be affected by the social composition of
other hunters, with more barks being produced when other hunters are closer affiliates,
suggesting flexibility in call production. The field experiment exploring joint action in
group hunts utilises the alarm calls of the chimpanzees’ prey species- the Colobus
monkey (Colobus guereza). Alarm calls produced by the monkeys when they were
being hunting by chimpanzees and in response to an eagle stimulus were played back to
dyads of affiliated males, and their vocal and behaviour responses recorded. Results
firstly indicate that chimpanzees recognise different Colobus predator alarm.
Furthermore, half of the trials with the Colobus hunting alarm elicited a vocal response
of barks from both of the males in the experiment, along with joint movement in the
direction of the playback. These initial results from a novel field experiment suggest
that the bark vocalisation is associated with the initiation of joint action in the context of
group hunting.
Type
Thesis, PhD Doctor of Philosophy
Rights
Embargo Date: 2019-06-01
Embargo Reason: Thesis restricted in accordance with University regulations. Electronic copy restricted until 1st June 2019
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