Postconflict behavior among Rhinopithecus roxellana leader males in the Qinling Mountains, China

Since reconciliation was first described more than 20 years ago, a large number of postconflict behaviors have been observed among females in many polygynous primate species. However, few studies have been conducted among males, perhaps due to the rarity with which they maintain friendly relationships with one another and their aggressive competition for resources. Although this is true for many primate males, Sichuan snub-nosed monkeys Rhinopithecus roxellana represent a potential exception as male cooperation has been known to occur. In this study, using postconflict/matched-control(PC–MC) and time-rule methods, we analyzed postconflict behavior among males and the possible occurrence of bystander affiliation or reconciliation. A total of 246 PC–MC pairs among leader males were obtained. On average, each leader male exhibited only 0.04 aggressive behaviors per observation hour, and conciliation among leader males occurred at a low rate (2.03%) relative to other primate species. The occurrence of consolation–affiliation interactions between focal males and group members other than former opponents differed significantly between PCs and MCs, which is the first time this has been confirmed among R. roxellana males. We discuss the results in light of recent theories concerning consolation in primates. The patterns of postconflict contact demonstrated that R. roxellana may be a unique species among colobines.