Establishment of a free-ranging colony of stumptail macaques (Macaca arctoides): Social relations I

Abstract

Data on the social behaviour of a free-ranging troop of Stumptail macaques are reported for a period starting of August 15th to November 7th of 1974.

Positive interactions take a greater part in the daily life of the troop than negative interactions. Individuals order themselves in an essentially linear dominance hierarchy and offspring rank immediately below their mother. Agonism and displacement are good predictors of dominance rank. Dominant individuals are a strong source of attraction for subordinates and the alpha male is a powerful social magnet for immatures.

Grooming was found to be correlated with dominance rank and individuals holding adjacent ranks tend to interact positively with one another. To gain access to dominant females, subordinates direct a great deal of positive behaviour to the female’s youngest offspring.

As social distance decreases the selection of a social partner becomes more strict and tends toward adjacency. However, factors such as motherhood, genealogical ties, and special relationships with non adjacent individuals, can override the tendency.

The direction and quantity of male-care displayed by the adult male and by juvenile males toward younger individuals was found to be influenced by the troop’s dominance patterns. Sex differences were found to exist in male-care received and a negative association was found with the age of the receiver.

Adult females are the main regulators of social relations and their rank and friendships provide their offspring with the social format, before puberty, in which they develop socially. The alpha male is the group protector, the performer of policing, an important element in the immatures’ social development, and a powerful source of attraction for all troop members.