INTERACTIONS BETWEEN FREE-RANGING GROUPS OF RHESUS MONKEYS

Interactions of three groups of rhesus monkeys were studied for 15 months on a small island off the coast of Puerto Rico. A stable dominance hierarchy positively correlated with group size persisted throughout the study. The overall interaction rate between groups was 0.36 per hour; significant differences among groups were found. Peripheral males were most often involved in interactions; in descending order of frequency other categories involved were central males, adult females, immature males and immature females. Because a few members of a dominant group often displaced an entire subordinate group, recognition of individuals from other groups and conditioning from previous encounters are assumed to occur. © 1968 S. Karger AG, Basel.