The Influence of Provisioning on the Intergroup Relationships of Rhesus Macaque in Hainan, China.

Abstract

Intergroup competition for limited resources is a significant selection pressure that drives the evolution of animal society. The rhesus macaque (Macaca Mulatta) is the most widely distributed nonhuman primate in the world and can adapt well to environments disturbed by humans. In some areas, human provisioning provides ample food resources for rhesus macaques, leading to an increase in their population size, inevitably affecting competition patterns within and between groups. In this study, we focused on seven provisioned groups of rhesus macaque in an eco-tourism park in Hainan, China, to verify how provisioning impacted their intergroup relationships. The results showed that: (1) Peaceful coexistence was the most common form of Intergroup contacts; (2) Provisioning led to an increase in intergroup contact and conflicts, but monkeys tended to avoid direct contact with other groups at main-provisioned sites with high conflict risk. (3) Larger groups did not interfere with each other's space use in the park, but smaller groups were more easily tolerated by other groups. (4) There were no strict linear dominance relationships among monkey groups. Overall, intensive provisioning satisfied the energy requirement of all monkeys in our study site, leading to a reduction in the relative benefit of intergroup conflict. Consequently, monkeys have adopted an intergroup contact strategy that avoids direct conflicts and prevents conflict escalation. We should pay more attention to the behavior patterns of provisioned animal populations, which will help us better understand how resources such as food have influenced the evolution of social strategies of animal groups, as well as how to manage such human disturbed animal populations in the future.