Impacts of Environment on Degree of Despotism in Semi-Free Ranging Japanese Macaques

Abstract

Primate societies have evolved social hierarchies when higher ranking individuals can gain access to differential benefits such as food resources and mating opportunities. In order to maintain high rank, individuals must uphold the social hierarchy and defend their position against lower-ranking primates. Different primate groups have varying degrees of hierarchical flexibility in which a population is despotic or tolerant depending on which confers individual benefit. This is often dependent on the particular environment. Tolerant hierarchies are typically seen in environments where group cohesion and cooperation are important for individual success, and are characterized by low rates of severe wounding, sharing of limited food resources, and frequent reconciliation following aggressive interactions. In contrast, despotic hierarchies are found where individuals can gain benefits by competing amongst each other for access to resources. They are distinguished by frequent aggression and wounding between individuals, restricted access to resources, and infrequent reconciliation. Japanese macaques (Macaca fuscata) are primarily characterized as having despotic hierarchies. Our research examines potential differences in hierarchies of Japanese macaques in wild and captive settings due to the differences in abundance and distribution of resources between the two environments. Through an examination of published studies, we will compare and contrast the environmental factors associated with despotic versus tolerant hierarchies in Japanese macaques. We will collect data on the Japanese macaque group at the Oregon National Primate Research Center (ONPRC). This research may provide insight into how different captive and wild environments affect primate behavior.