Proboscis monkeys are specialized riverine primates that have proven extremely difficult to maintain in captivity, raising questions about the ethics of keeping them in zoos.
Proboscis monkey welfare in zoos represents one of the clearest examples where conservation value and welfare considerations create ethical complexity. Wild populations are declining rapidly, creating a conservation case for captive preservation. But captive proboscis monkey welfare has historically been poor — high mortality from dietary incompatibility, social disruption, and stress. Only facilities with exceptional botanical access and specialized expertise can maintain proboscis monkeys with adequate welfare. The ethics of keeping this species in captivity require honest assessment of whether individual welfare can be maintained at a level that justifies conservation purposes, or whether resources are better directed toward wild habitat protection.