Hippopotamuses require deep water access, social companionship, and appropriate management of their complex social dynamics to maintain welfare in zoo settings far from their African river habitat.
Hippopotamus welfare in zoos is fundamentally dependent on the quality of water access provided. Hippos spend the majority of their lives in water — not as an optional enrichment activity but as a thermoregulatory necessity. Inadequate pool size, depth, or quality causes skin problems, overheating, and prevents the natural floating, diving, and submerging that characterise hippo behaviour. Pools must be deep enough for full submersion and large enough for the animals to move freely. Social management of hippos requires expert understanding of their territorial and dominance behaviour — adult bull hippos are highly aggressive toward each other and must be managed carefully to prevent serious injury. Mixed groups can be managed successfully but require space that allows adequate separation of incompatible individuals. Evening grazing behaviour — hippos naturally leave water at dusk to graze — should be facilitated by providing grass grazing areas accessible overnight. Positive reinforcement training enables health monitoring procedures without dangerous physical restraint of an extremely powerful and potentially dangerous animal.