Post-conflict behaviour of spectacled Langurs (Trachypithecus obscurus)

Abstract

Studies of post-conflict behaviour in primates have two aims, 1) to uncover the fundamental mechanisms underlying conflict resolution, 2) to integrate patterns of reconciliation within broad models of socio-ecology. Comparative studies are vital in answering questions related to both of these problems. So far, research has focused mainly on members of the cercopithecine family and the great apes. Hypotheses derived from these studies predict that the "quality" of dyadic relationships, measured according to their value in terms of reproductive fitness, is a good predictor of the tendency to reconcile; and that high conciliatory tendencies are often associated with a high degree of social tolerance. In this study, two groups of spectacled langurs (members of the colobine family) were demonstrated to reconcile at high rates (41.3% and 51.3% of conflicts) and display relatively egalitarian social structures. Highly affiliative dyadic relationships were associated with high conciliatory tendencies. Other variables such as kinship and rank had little effect. In agreement with previous studies concerning highly conciliatory species, former opponents engaged in a specific behaviour (ventro-ventro hugging) during reconciliation which make these reunions highly visible or "explicit". Victims of aggression also contacted uninvolved third parties at high rates, and here too, hugging was demonstrated to occur significantly more often in this context than during control periods. There was some evidence of consolation, the first for any monkey species, where the distribution of hugging following a conflict was examined in one of the groups, although small sample sizes precluded its confirmation.