Conflict resolution in sooty mangabeys

Behaviour associated with conflict and conflict resolution (i.e. aggression, aid to the victim, join with aggressor, reconciliation) and the individuals involved (kin versus non-kin) provide an important means by which to compare the social systems of different primate species. To better understand the social nature of a little known primate species, sooty mangabeys, Cerocebus torquatus atys, aggression and its sequelae were studied in a captive group over a period of 1 year for a total of 307 agonistic episodes. Most aggression between sooty mangabeys did not involve contact (53%) and contact that did occur was controlled. Aid to the victim following agonistic interactions was recorded during 4·4% of the episodes in sooty mangabeys and 15·6% in rhesus monkeys, Macaca mulatta, in a specific comparison between these two species. Additionally, for mangabeys, victims involved in heavy aggression received aid more frequently than victims involved in light aggression. Regarding post-aggressive behaviour, interaction with the opponent was initiated following the aggressive episode during 55% of the post-conflict sessions compared with only 2% of the matched controls. By far the most common interaction initiated by the victim following an aggressive episode was returning to or staying with 1 m of the aggressor (94%). This behaviour was accompanied by a hindquarters present while looking at the opponent over the shoulder or simply returning to or staying within 1 m and looking at the opponent. Importantly, kinship did not play a role in influencing the frequency of interactions following aggressive behaviour. Thus, sooty mangabeys do not exhibit damaging aggression under stable social conditions, perhaps influencing the fact that aid to the victim in this species is infrequent, and non-aggressive interactions between opponents occur following the majority of agonistic episodes without regard to kinship.