Agonistic support towards victims buffers aggression in geladas (Theropithecus gelada)

Agonistic support occurs when a bystander intervenes in an ongoing conflict. The consequences of agonistic support may differ when provided to victims or aggressors. Supporting victims may not only protect them, but also limit the escalation of aggression among group members. Our results on Theropithecus gelada showed that support was preferentially directed towards victims and high-ranking individuals provided the highest levels of support. Whereas the support towards the aggressor had no effect in reducing its renewed aggression, it increased the frequency of subsequent conflicts among fellows. The support towards victims significantly reduced subsequent aggression both towards the victim and among other group members. The support was biased towards victims who were unrelated and shared weak bonds with the aggressors. In conclusion, victim support may be a social tool, which intervenes when other mechanisms are less likely to occur such as the case when the opponents are not kin or friends.