Hippopotamuses are semi-aquatic megafauna with complex welfare requirements including deep water access, species-appropriate social structure and sufficient space for a territorial and potentially aggressive species.
Hippopotamus welfare in captivity hinges primarily on water access. A hippo without access to deep water - deep enough to fully submerge - experiences thermoregulatory stress, skin deterioration and loss of the aquatic social environment that is central to natural hippopotamus life. Historical zoo hippo facilities frequently provided inadequate pools; modern facilities that take hippo welfare seriously provide deep, large pools with both underwater visibility for enrichment and land areas with substrate variation. Social management requires careful assessment of compatibility - hippo aggression can cause serious injury, but social isolation also causes welfare deficits.