Aggression does not increase friendly contacts among bystanders in geladas (Theropithecus gelada).

Aggression within a social group may affect bystanders' affinitive behaviour with other bystanders. After a conflict such affiliations, termed 'quadratic', may serve to reduce tension. This particular kind of conflict management has been found in hamadryas baboons. Following the classical and well-established approach for studying post-conflict behaviour [post-conflict/matched control method (PC/MC)], we collected behavioural data on a group of geladas (Theropithecus gelada) in order to check for the presence of quadratic affiliations. A total of 192 PC/MC pairs were collected on both adults and immature individuals. We did not find any increase of affiliation levels between bystanders during PC compared with MC condition. The distribution of affinitive quadratic interactions was not affected by either kinship or relationship quality of bystanders. Moreover, comparison of yawning and self-scratching behaviours (two of the typical non-primate displacement activities under stressful situations) recorded during PCs and MCs did not show any variation in the two conditions. Probably, due to the male tolerance and social cohesiveness in geladas, witnessing a fight does not necessarily induce a sufficient increase of tension in bystanders to be reduced by quadratic affiliation.