Non-human primates in zoos require complex social environments that challenge institutions to manage group dynamics, introductions, and individual welfare carefully.
Primates in inadequate social situations suffer psychologically in ways that are highly visible - self-biting, hair pulling, rocking, and other stereotypic behaviors clearly indicate poor welfare. Social isolation in early life causes lasting psychological damage analogous to human social deprivation effects. Group management failures resulting in serious injuries from conspecific aggression are a welfare emergency. The complexity of primate social lives - alliance formation, reconciliation behavior, political maneuvering - means welfare assessment must go beyond physical health to assess social engagement and behavioral complexity. Modern accredited facilities have made substantial progress in primate social welfare but significant variation between institutions remains.