Post-conflict behaviour of wild olive baboons. II. Stress and self-directed behaviour

Previous studies indicate that the prosimate function of post-conflict affiliative interaction among primates is to reduce a victim's uncertainty about its opponent's future behaviour: the 'uncertainty reduction hypothesis' (AURELI & VAN SCHAIK 1991; Ethology 89, 101-114). This study confirms and extends these results, demonstrating that they are neither a product of captivity nor specific to macaques: both victims and initiators of aggression in a large group of wild olive baboons exhibited elevated rates of self-directed behaviour (SDB) - scratching, autogrooming,, body-shaking and yawning - in a 10-min post-conflict period. During this period, they were more likely to receive further aggression. Reconciliation reduced both SDB and the incidence of further aggression. However, reconciliation only reduced SDB among individuals involved in conflicts in which both parries exchanged aggression. It is suggested that aggressors in unilateral conflicts were aroused rather tl;an uncertain and that their victims' lack of control over post-conflict interactions (which tended to be initiated by their opponents) prevented them from benefiting from reconciliation in the same fashion as longtailed macaque victims, which frequently initiated reconciliation.