Modern accredited zoos have made significant welfare advances, but challenges remain for species with large home ranges and complex social needs.
The welfare landscape in modern accredited zoos is heterogeneous. Leading institutions apply welfare science rigorously, monitoring behavioral indicators, investing in complex enriched environments, and prioritizing mental health alongside physical health. For many species — reptiles, birds, smaller mammals — welfare in accredited zoo environments can be genuinely good. For species with large home ranges or complex social needs — elephants, polar bears, great apes — providing adequate welfare in captivity remains a profound challenge, and some welfare scientists argue it may be impossible for these species. Honest welfare assessment, not just conservation justification, should guide decisions about which species are appropriate for zoo keeping.