Social Dominance in a Group of Captive Mandrills (Mandrillus sphinx): An Analysis of Behaviour Indices

Abstract

<p>Social dominance has been defined and measured in various ways in studies of non-human primate social organization. In this project, dominance is defined operationally as an inter-correlated cluster of behaviours, one of which is the ability to aggress on an individual without that individual responding with aggression. Behavioural observations are conducted on a captive group of mandrills (Mandrillus sphinx) in order to determine whether dominance relationships are present and to examine the validity of traditional measures of dominance. A cluster of inter-correlated behaviours is identified which indicates dominance and ranks the animals into a linear hierarchy. The primary significance of the dominance hierarchy lies in conferring predictability to certain limited types of behavioural interactions, including agonistic encounters, non-agonistic approach-retreat patterns, and non-agonistic presenting. Delineation of such clear-cut dominance hierarchies is rare in non-captive situations, and possible reasons for this difference are discussed. An improved methodological approach to the study of dominance is proposed as a basis for comparative analysis utilizing the dominance concept.</p>