Consensus Decision Making During The Collective Movement Initiation In The Golden Snub-Nosed Monkey (Rhinopithecus Roxellana)

Faced with a precarious living environment,animals always live in carefully.Whatever how cautious with animal individual,single individual remain vulnerable to the dangers of environment.Cause of the absolute power for a single individual grew so slowly,animals have evolved group-living cope with opportunities and challenges.Living in group,benefits and costs coexist.Such as individual in a group,can reduce the consumption of searching for food,increase the early warning of potential risk,reduce the probability by predators attacked and so on.However,in order to obtain benefits by group-living,individuals have to sacrifice part of their willingness and motivation to constantly adjust their behaviors so as to harmonize with the activities of the animal group and maintain the cohesion of the group.If an individual persists go it along,without considering other members of the group,the individual will excluded by group,not only losing the benefits of group-living,but being directly exposed under potential dangers as well.Therefore,in order to maximize the benefits of social life,members of an animal community need to make collective decisions about when and where to feed,move,and rest and so onThe collective movement which is the most direct and effective tool to explore collective decision-making on its mechanism.Collective movement: animal group that decide to move quite synchronously,together in the same direction(which implies the animals have a choice between different alternatives)and maintain cohesion until the group stops moving or starts a new activity,all resulting in a change of location.Collective mobility not only involves information transmission mechanism and community coordination mechanism within the goup,but also involves decision-making mechanism and individual decision's contribution and rised to collective decision making.It has become the "golden key" to explore collective decision making.This study was aimed to golden snub-nosed monkey group which is located on southern slopes of the Mts.Qinling,Shaanxi Province,China.Based on field observation and close observation technology,we are trying to explore the decision-making mechanism as i)what is the decision making type in golden snub-nosed monkey? ii)what and which factors will contribute to results of the decision-making? iii)How do individuals participate in decision making during collective movement?Study on the decision-making process of golden monkey collective initiation We collect 1223 datum records relevant to decision initiation from six OMUs.The results indicate that collective movement initiation could be divided into two continual but relatively independent processes: decisions on moving direction and movement implementation.In both processes,adult individuals are more likely to initiate the decision-making,while other adults vote on initiator's preference,with a threshold,a supporting number required for a success.Thus,voting behavior and quorum fulfillment contribute to a successful decision-making.Adult individuals play important role in making decisions for moving direction and implementation.For a successful collective movement initiation,the individuals being more central in grooming network initiate decisions more frequently than the others,and attract voters more easily.Furthermore,following the initiation,at least four positive voters are required for a direction decision and at least three positive voters are needed for the decision on movement implementation,which could be considered as the threshold of quorum numbers required for a successful decision.The individual participation in collective movement decision making In this study,865 collective mobile initiation decisions of golden monkeys in Qinling Sichuan were collected.Our results indicate that there exists a threshold number for individuals participating in the decision-making process that can trigger a successful decision on a new directed collective movement.When the number of individuals participating in the decision-making is three or four,the probability rate of success lies between 28.5% and 72.8%;if the number of individuals exceeds five,this rate is 100%.This method matches the quorum mechanism hypothesis.However,although many individuals from the frontline are engaged in the decision-making process,others follow through a mimetism mechanism,which implies that the individuals who exert a significant influence in daily social interactivity play an important role in decision-making.Thus,our findings in this nonhuman primate species can provide a good reference to interpret the scenarios that may have occurred during the evolutionary development of our human ancestors.The following three problems should be paid attention to and mainly solved in the future research1.In this study,we only focus on individuals' behavior in collective decision making.However,in our observation,we found that information communication always goes through the whole process of collective movement.Information exchange is an important content to explain the collective decision-making mechanism and need more attention in the next research.2.The golden snub-nosed monkey society which famous by multi-levels social system.In such a society,different levels are orderly in collective movement.In this research,we only focus on OMU level and does not involve other levels.Therefore,in the future research,the goal should be gradually extended from OMU level to whole community level.3.During the collective movement,the decision-making process takes less than one minute.Such a fast process includes coordinating and synchronizing mechanisms.In this study,we recorded data with the VCR.Although we were able to record the movement of OMU date,we were unable to do anything about the movement of the community data.Therefore,how to improve the research method has become an urgent problem to be solved in the future.