The mandrill (Mandrillus sphinx) is the world's largest monkey and one of the most visually striking primates. Captive management has advanced significantly, with evidence that large, socially complex groups in naturalistic enclosures produce far better welfare outcomes than traditional small-group zoo housing.
Mandrills in small zoo groups without adequate social structure develop abnormal behaviours: dominant males show hyperaggression without appropriate social hierarchy, and subordinate animals cannot express submissive signals effectively in restricted spaces. Large naturalistic groups with multiple adult males show more stable hierarchies, lower aggression rates, and higher reproductive success. Enrichment provision — including whole fruits embedded in bark, puzzle feeders, and browse — reduces stereotypic behaviour and increases species-typical foraging time. Welfare monitoring in mandrill groups must include individual tracking of social relationships, since subordinate individuals in poorly managed groups may be chronically stressed despite appearing physically healthy.