Primates are highly social animals whose welfare in captivity depends critically on appropriate social grouping, with isolation or inadequate social environments causing severe psychological suffering.
Primate welfare in captivity is fundamentally compromised when social needs are not met. Solitary housing of social primates causes depression, anxiety, and the development of severe stereotypies and self-injurious behavior that indicate extreme psychological suffering. Historic practices of isolating primates for management convenience or research requirements have caused profound welfare harm. Modern zoo standards require social housing for primates with very limited exceptions, recognizing social companionship as a basic welfare need equivalent in importance to food and shelter. Retired research primates require particularly careful rehabilitation into social groups after potential isolation.