Coping with conflict during initial encounters in chimpanzees

When strangers meet, conflict is likely to arise from incompatibilities in motivations and expectations, as well as from the absence of predictability in interactions, This study explores the mechanisms that mitigate aggressi on, permit mutual evaluation, establish tolerance, and facilitate the devel opment of social bonds between unfamiliar chimpanzees (Pan troglodytes). Da ta collected during the initial half-hour of the introduction of 33 unfamil iar pairs (16 female-male and 17 female-female) at the Yerkes Primate Cente r and Detroit Zoo were used to assess the sequence of events during initial encounters and the function of different behaviour patterns in the formati on of relationships. Initial encounters followed a regular sequence of inte ractions (i.e. a 'species-typical etiquette'), commencing with agonistic be haviour, followed by brief friendly touches, and finally allogrooming. Brie f friendly touches, which are associated with conciliatory and tension-redu cing functions in established relationships, appeared to serve an evaluativ e function related to status differentiation during initial interactions. I n fact, individuals more closely matched in competitive ability (inferred f rom their eventual dominance rank distance) exchanged friendly touches at h igher rates than those more obviously mismatched. These evaluative touches may represent a safer alternative to more assertive interactions when asses sments of competitive ability are required in situations likely to escalate . Allogrooming promoted the development of tolerance and relaxed proximity; it was, in fact, effective in reducing agonism and negative-outcome approa ches. Allogrooming may take on a particularly important role in reducing ag onism because it begins the commerce of benefits that balance the dispersiv e competitive forces and enable cohesive social groupings.