Differences In Social Play Types And Functions Of Immature Tibetan Macaques(Macaca Thibetana)

Immature individuals are an organic part of the community of non-human primates.They can maintain the stability and long-term development of the group through various types of social behavior interaction and the construction of complex social relations with adult individuals.A large number of studies have confirmed that different from adults,the social interaction of minors is mainly based on play behavior(mainly including object play,solitary play,social play,etc.).Social play(play behavior involving two or more individuals)was once considered to be an interesting but non-functional behavior pattern among immature individuals.Since Burghardt proposed the criteria of social play behavior in 2005,systematic studies have found that social play is restricted by many social factors such as kinship,maternal rank,etc.,and also affects the social relations and development prospects of immature individuals.These results suggest that social play has important sociological functions(such as motor-training hypothesis,social bond hypothesis,cognitive hypothesis,etc.).At the same time,primates have a long immature stage,which provides an opportunity platform for the individual development,behavior training,social learning and gradually growing up for adults.With the growth of immature individuals,what are the differences between different types of social play patterns? At the same development stage,what are the differences of social play behavior between different genders? Answering these questions will help us to understand the functions and differences of social play,and further understand the social role and functional role of immature individuals in social groups.In this study,wild Tibetan macaques(Macaca thibetana),which lives in Huangshan,Anhui Province,was selected as the research object.The natural occurrence behavior data of YA1 group in the forest was recorded from January 2019 to June 2019 by using the focal animal sampling method,one-zero sampling method and ad libitum method.These include: social play,social grooming and aggression.By observing the natural state of immature individuals and adults,the differences of play behavior and social behavior between males and females of different age classes were compared to determine the functional differences of social play.The main results are as follows1.Social play is the main social behavior pattern of immature individuals.Immature individuals occupy the central position in the social play network,and the eigenvector center is higher.In the social grooming network,the immature individuals are at the edge,and the adult individuals are more important.We believe that the trend of gradually moving away from the network center of social play and gradually approaching the network center of social grooming with the growth of individual age is the trend that individuals gradually mature and integrate into adult society.2.The main function of social play behavior of infants is motor skill training.There was no significant difference in the frequency of social play,the proportion of aggressive/ affiliative play,the frequency of intrasexual grooming individuals,and the frequency of intrasexual aggression between male and female infants.Therefore,both male and female infants support the motor-training hypothesis of social play.In other words,in order to ensure their own survival,both male and female infants carry out social play exercise to improve their survival rate.Therefore,their play behavior patterns are similar.3.The main function of individual social play behavior is social bond function.Juvenile males participated in social play more frequently than female,and the proportion of aggressive play was higher.In view of the fact that the male of the wild macaque is disperse,the female philopatric,we believe that juvenile males develop aggressive skills through a large number of aggressive play in order to gain more benefits from entering the new group in the future,while females exercise the skills of maintaining affiliative relations through affiliative play.Although there is no significant difference between juvenile males and females intrasexual aggression and intrasexual grooming,there are significant differences between adult males and females.We believe that there is only a tendency of differentiation between male and female in juvenile period,but there is significant difference in adult.4.The social play behaviors of immature individuals and adults contribute to the construction of social relations between adults.Immature individuals only play with adult males,the number of social playing of adult males was positively correlated with the number of bridging,and the number of bridging was positively correlated with the grooming network of adult males.We believe that the play between adult males and immature individuals can help adult males gain benefits in adult society.Similar to other studies reported in the literature,this study proves that the functional hypothesis of social play is applicable to wild Tibetan macaques.Different from previous studies,this study found that the social play pattern of infants supports the motor-training hypothesis,while the juvenile individuals support the social cognition hypothesis,and the adult social play has other functions.We believe that the functions of social play are complex and diverse,which can't be explained by a single functional hypothesis.There are differences in social play functions among individuals of different ages.This study explores the function of social play from various behavioral perspectives and different age levels.It provides case support for the study of social play in non-human primates,and provides guidance for further understanding the growth and development of social animals.