Polar bears are among the most challenging species to maintain in captivity from a welfare perspective, with stereotypic pacing a persistent indicator of psychological distress in even well-resourced zoo settings.
Polar bears represent the clearest case of a species for which captive welfare requirements fundamentally cannot be met within zoo infrastructure. The scale of space needed for psychological wellbeing — hundreds of thousands of square kilometres of sea ice environment — is not approximable in any zoo setting. The consequence is persistent stereotypic behaviour that indicates chronic psychological distress even in the best-designed facilities. Unlike some other species for which enrichment and social management can substantially address welfare needs within realistic zoo space, polar bears appear to require spatial scale for which there is no adequate substitute. The welfare case for not keeping polar bears in standard zoo enclosures is strong, and the conservation case is weak given the impossibility of reintroduction. Larger, more naturalistic facilities such as wildlife parks in cold climates may offer partial improvement.