Social functions of relaxed open-mouth display in golden snub-nosed monkeys (Rhinopithecus roxellana)

摘要

Relaxed open-mouth display serves important social functions in relation to submission,reconciliation,affiliation and reassurance among non-human primate societies;however,quantitative evidence on this behavior remains insufficient among multi-level social groups.From July to November 201 6,we examined four potential functions of the relaxed open-mouth display during pairwise,intra-unit social interactions among 18 free-ranging adult and sub-adult golden snub-nosed monkeys (Rhinopithecus roxellana) who belonged to three one-male,multi-female units (OMU) at Dalongtan,Shennongjia National Park,China.Results showed that:compared with no relaxed open-mouth display,(1) the occurrence of displacement by a dominant individual approaching a subordinate was lower and the distance of the subordinate to the approaching dominant was shorter when the subordinate showed open-mouth display;(2) relaxed open-mouth display reduced the probability of continued attack for victims of aggression and allowed victims to achieve closer proximity to the aggressor during post-conflict periods;(3) relaxed open-mouth display by dominant individuals allowed them to achieve closer proximity to subordinates;and (4) the exchange of relaxed open-mouth display had a greater impact on the outcome of interactions than one individual alone giving this signal.These findings suggest that relaxed open-mouth display serves important functions regarding submission,reconciliation,affiliation and reassurance in coordinating social interactions within OMUs in golden snub-nosed monkeys.