Common marmosets are small New World primates with highly complex social lives; their welfare in captivity depends on appropriate group structure, cognitive enrichment, and space.
Marmoset welfare in both zoo and laboratory settings is critically dependent on social housing. Solitary or paired housing fails to meet their cooperative social needs; groups of at least 4-6 allow meaningful social repertoires including allogrooming, play, and cooperative infant care. Enclosures require dense vertical structure — branches, ropes, and shelving at multiple heights — to reflect their arboreal lifestyle. Cognitive enrichment such as puzzle feeders, novel objects, and training for voluntary cooperation in veterinary procedures significantly improves welfare. In research settings, marmosets present a particular welfare challenge given their sensitivity to social disruption during experimental protocols.