Changes in the dominance hierarchy of captive female Japanese macaques as a consequence of merging two previously established groups.

Dominance hierarchies play an important role in reducing competition and aggression in social animals. In zoos, changes in group composition are often required due to management protocols, but these changes may have long lasting effects on dominance hierarchies, and, consequently, the wellbeing of the animals. We studied the changes in the female dominance hierarchy that occurred both during and after the formation of a group of 10 adult Japanese macaques at the Zoo de Granby by combining members from two previously established groups. There was no significant correlation between individual ranks in the old groups (groups A and B) and their ranks in the new group (group AB), indicating a significant change in the hierarchy. Alliances between kin appeared to be important in determining rank; when the sister of the dominant female was removed from group AB, the hierarchy changed significantly a second time. The average standardized rank of individuals added later in the formation process of group AB was not different from those added earlier. Ranks in the group AB did correlate with age of individual at the beginning of the field season, but not at the end, after the shift in hierarchy occurred. Zoo management must be aware of the consequences small changes in a social group can have when removing and transferring individuals in both primates and in other social species. Zoo Biol. 35:505-512, 2016. © 2016 Wiley Periodicals, Inc.