How modern zoo primate programs are addressing social complexity requirements and why solitary housing of social primates is a major welfare failure.
The welfare of primates in zoos is perhaps better understood than that of any other captive wild animal group, due to extensive research informed by conservation field studies. This understanding makes historical practices of solitary primate housing all the more concerning in retrospect - and makes the persistence of inadequate social housing in under-resourced facilities all the more unacceptable. Social primates deprived of conspecific interaction show behavioral pathologies that unmistakably signal profound psychological suffering. The welfare standard is clear: social primates must live in appropriate social groups. Achieving this standard across all primate-holding facilities globally requires continued advocacy and regulation.