The regulation of influence positions in a chimpanzee society

Social dominance has since a long time been regarded as one of the major aspects of the organisation of animal societies. Usually "dominance behaviour" is mentioned in one breath with "aggression". To be sure, aggressive behaviour is undoubtedly an important means to achieve priority and a position of social independence and freedom. But it is certainly not the only means. Recent studies of the social processes observed in the communities of higher primates, including our work in the chimpanzee colony of Burgers' Zoo at Arnhem, reveal that infuence may be achieved by a process of societal transactions.

Thus, the dominance positions of adult chimpanzee males depend on coalitions that are opportunistically formed. This is illustrated by the history of power take-overs and of the attempts to achieve them, such as they can be observed in the colony. It appears that the provision of support in these coalitions is not without risks for the supporter though it is clearly advantageous to the animal receiving the support. However, it may be assumed that also the supporter may experience some advantage. Our present research is directed, among other things, at assessing the presence and nature of the supporters' compensations.

The above considerations were illustrated for the Meeting's participants during an excursion to the colony itself.

In the course of this excursion, the participants witnessed a remarkable incident (see "A joke" on this page)

Risks of aggression

Frans de Waal recounts in "Peacemaking among primates" (1988) how one of the adult males in Arnhem was seriously wounded (he died later the same day) by two rival males. After the death of this male, it almost seemed like the threshold for more serious aggression between adult males was lowered. On three occasions fights were observed where one of the males lost a digit (Otto Adang, personal communication in de Waal, 1988)