Hippopotamuses in zoos require specialized facilities with adequate water depth for natural behavior, appropriate social grouping, and management that accounts for the species' complex and potentially dangerous social dynamics.
Hippo welfare in zoos is primarily determined by water quality and access, social group composition, and the ability to thermoregulate through aquatic behavior. Hippos that cannot fully submerge experience thermal stress and skin drying that causes significant discomfort - they lack sweat glands and secrete a specialized reddish fluid that functions as a sunscreen and moisturizer but requires aquatic supplementation. Social management is critical and complex: dominant bulls will seriously injure or kill subordinates if group dynamics are not carefully managed, making space and multiple pool access important welfare infrastructure.