Hippos are highly territorial, semiaquatic megafauna whose welfare in captivity requires substantial water access, careful social management, and attention to their complex behavioural needs.
Hippo welfare in zoos is substantially dependent on water access quality and quantity. Insufficient pool depth or area forces hippos to spend time out of water, leading to skin cracking and sunburn, as hippos lack functional sweat glands and depend on water for thermoregulation and skin protection. Their secreted red fluid, sometimes called blood sweat, is a natural UV-protective and antimicrobial substance rather than actual sweat, but it does not substitute for water immersion. Social management is critical; incompatible hippos in confined spaces can suffer severe injuries from territorial aggression. Dental care for hippos in zoos is a specialist challenge, as their continuously growing tusks require management. Well-managed hippo exhibits with deep pools, grazing areas, and appropriate social groupings can support good welfare.