Drills are critically endangered African primates with complex social structures requiring expert management in zoo settings to achieve good welfare outcomes.
Drill welfare in captivity requires addressing the social and cognitive complexity of this intelligent primate. Solitary or pair housing fails to meet social needs and leads to stress behaviors including self-directed aggression and stereotypies. Bachelor groups are an effective management strategy for surplus males, providing social interaction without reproductive competition. Space requirements are substantial — drills are active, wide-ranging primates that benefit from large, complex habitats with varied substrates and climbing opportunities. Keeper relationships are important for voluntary health check cooperation, which reduces stress during veterinary procedures. Behavioral management programs using positive reinforcement training improve welfare outcomes and allow collaborative care. Drill conservation education is important given the species extreme rarity and the threats from hunting.