Visual Communication In Collective Decision-making In Tibetan Macaque(Macaca Thibetana)

Social animals often move together to achieve group foraging,collective defense and cooperative reproduction,so as to maintain the advantages of group-living.However,because the interests and needs of group members are different,it is difficult for them to reach the consensus on direction and time of movement.Therefore,animals often move in groups by negotiating decisions.In the process of collective decision-making,individuals can achieve activity consistency through the transmission of visual signals,which is a key link of group decision-making in animals.However,the behavioral mechanism of such information transmission and communication response is still unclear.This study was conducted during the mating season(September 2019 to January 2020)and non-mating season(May 2020 to June 2020)of Tibetan macaques.Focal animal sampling method and all occurrence sampling method were used for data sampling.So as to probe into the specific mechanism of visual communication in collective decision-making,we conducted7-month behavioral data sampling of Tibetan macaque YAl group in Huangshan,Anhui Province.The results are as follows:(1)During the study period,169 successful collective movements were recorded,including 10 young-adult males,20 young-adult females,3 adolescent males and 2 adolescent females.Among them,there were 64 collective movements(38%)with visual signals and 105 collective movements(62%)without visual signals.A total of 706 visual signals were observed,including 317 back-glances signals(45%)and 389 pauses signals(55%).All individuals were found to back-glance and pause signal during the collective movement.(2)No difference was found between the back-glance signal and the pause signal(P>0.05)markedly during the mating season,and there was no difference between the back-glance signal and the pause signal markedly during the non-mating season(P>0.05).No significant difference was found between the mating season and the non-mating season in the back-glance signal(P>0.05),and no significant difference was found between the mating season and the nonmating season in the pause signal(P>0.05).(3)There was a significant negative correlation between the frequency of the initiator’s back-glance signal and the number of followers in the collective movement of Tibetan macaques(N=14,r=-0.873,P<0.01).(4)There was a significant negative correlation between the frequency of the initiator’s pause signal and the number of followers in the collective movement of Tibetan macaques(N=14,r=-0.581,P<0.05).(5)As for the back-glance signal,the frequency of the participants with large number of relatives was greatly higher than that of the participants with small number of relatives(P<0.05).The emission frequency of the participants in the back position was greatly higher than that of the participants in the front position(P<0.05).No difference was found in emission frequency signally between males and females(P>0.05).No difference was found in the distribution among adolescent,young-adult,middle-aged adult and old-aged adult markedly(P>0.05).No observable difference was found among different ranks(P>0.05).There was no difference in emission frequency notably among participants with different social centrality(P>0.05).(6)As for the pause signal,the frequency of participants with high social centrality was greatly higher than that of participants with low social centrality(P<0.05).The emission frequency of the participants in the back position was greatly higher than that of the participants in the front position(P<0.05).No difference was found prominently in emission frequency between males and females(P>0.05).No difference was found in the distribution prominently among adolescent,young-adult,middle-aged adult and old-aged adult(P>0.05).No significant difference was found among different ranks(P>0.05).No difference was found prominently in emission frequency between participants with different number of relatives(P>0.05).This study suggests that visual signal of Tibetan macaque has the function of recruiting and monitor and all member can affect collective behavior through visual communication.Position and social centrality and number of relatives are the main factors influencing the visual communication of Tibetan macaque.This study provides a new perspective for revealing the relationship between social animals’ communication behavior and group cooperation,and for exploring the relationship between social animals’ communication behavior and group maintenance is of obviously significance.