A Preliminary Study On Social Laterality In Northern Pig-tailed Macaques(Macaca Leonina)and Sichuan Snub-nosed Monkeys(Rhinopithecus Roxellana)

Social laterality is defined as the behavioral laterality during the interaction between animal group members in the social environment.Social laterality has important evolutionary significance for both individual and group adaptive survival.Based on phylogenetic relationships,this study applied the quantitative multi dimensional method to investigate the basic characteristic of social laterality in northern pig-tailed macaques(Macaca leonina)and Sichuan snub-nosed monkeys(Rhinopithecus roxellana)for the first time.It was found that:1)the front preference was found on the group level for both species;2)in the lateral condition,Sichuan snub-nosed monkeys displayed a certain tendency toward left preference whereas northern pig-tailed macaques displayed a certain tendency toward right preference,both of which did not reach at the significant level for both species;3)there was no sex difference and age-group difference for the direction and strength of social laterality for both species.Two Old World monkeys species showed similarities and differences on social laterality during this positional preference study,which reflect the evolutionary adaptation of primate behavior to some extent.