Hippopotamuses spend most of their time in water to regulate temperature and protect their skin. Zoo facilities must provide adequate aquatic environments and careful social management.
Hippopotamus welfare in zoos requires large, deep pools that allow full submersion and buoyancy — hippos are semi-aquatic animals that move gracefully underwater despite their bulk on land. Without adequate pool depth and area, hippos cannot thermoregulate properly, their skin dries and cracks, and behavioral frustration is evident. Social management is particularly challenging: male hippos are extremely aggressive toward each other and must be managed carefully to prevent serious injuries. Female groups can coexist with sufficient space, but crowding produces tension and aggression. Breeding management requires separating male calves before maturity. Feeding hippos the correct diet — primarily grass and hay — prevents obesity, which is a welfare problem in animals with limited exercise opportunities in captivity. Pool water quality and filtration are significant husbandry challenges given the volume of waste hippos produce.