Spatial organization of captive monkeys (Macaca nemestrina)

Abstract

An artificial group of 18 pigtailed monkeys, selected by sex and size (age) to simulate the composition of natural groups of macaques, was formed. All were strangers to each other. Observations were made over five months. Data on the monkeys' resting and clustering locations in the compound were analyzed in two ways.

Spatial organization emerged about one month after the group was formed when the group acquired a competent leader. The leader, certain high ranking females, and/or females in estrus were seen consistently in a geographically central area of the compound and therefore were termed central monkeys. This central subgroup, coherent in terms of area and roles, persisted throughout the study. Development of increased group structure was also indicated by increased stability of dyadic affectional relationships.

The study indicates that social organization of the pigtailed macaque will develop when some of the environmental and prior experience variables are controlled. The results highlighted the leader's role and suggest that it is at least as essential in social organization as kinship and factors inherent in a natural environment. Estrous cycles of females and seasonal variations of temperature in the compound were other factors affecting spatial and social relationships of the group members.