Postconflict affiliation and stress-related behavior of long-tailed macaque aggressors

Abstract

Previous studies on macaques and baboons showed that after agonistic conflicts aggressees as well as aggressors show an increase in stress-related behavior such as scratching. Reconciliation reduces stress-related behavior of the aggressee. We investigated the influence of various affiliative postconflict behaviors of the aggressor on the aggressor's scratching rates in captive long-tailed macaques: reconciliation, contacts with the aggressee's kin (or substitute reconciliation), and contact with other group members (or triadic affiliation). After a conflict, the aggressor showed an increase in rates of scratching. Scratching rates were reduced after reconciled conflicts compared to nonreconciled conflicts. Substitute reconciliation did not reduce scratching when we controlled for the influence of reconciliation, i.e., the aggressor might not interpret it as a substitute for reconciliation. Triadic affiliation did not reduce scratching rates, hence, triadic affiliation probably does not console the aggressor. Scratching rates after reconciliation are significantly lower than scratching rates after triadic affiliation. This proves that the stress-reducing effect of reconciliation is not due to the calming effect of general body contact but that the stress reduction is specifically associated with contacts with the former opponent. The contestants are anxious about their relationship, and only reconciliation takes away this anxiety. Reconciliation is thus an important social repair strategy.