Zoo Hippopotamus Welfare and Space Needs

Hippopotamuses spend up to 16 hours daily submerged in water in the wild and have specific behavioral and social needs that many zoo hippopotamus exhibits fail to adequately address.

Key Facts

Wild hippos spend the day in water to regulate temperature and skin moisture, emerging at night to graze
Hippo skin secretes a reddish fluid that acts as sunscreen and antimicrobial protection, requiring water access to remain healthy
Common hippopotamus are classified as Vulnerable with populations declining due to habitat loss and hunting
Zoo hippo exhibits often provide insufficient water depth for the animal to submerge fully and rest underwater
Hippos are highly social in the wild but can be fatally aggressive toward unfamiliar conspecifics in confined spaces
Dwarf hippos are also kept in some zoos and have different social and habitat requirements than common hippos

Welfare Considerations

Hippopotamus welfare in captivity centers primarily on water access. The large, deep pools required for hippos to exhibit normal rest and thermoregulation behavior are expensive to maintain, and many zoo exhibits provide pools too shallow for full submersion. Hippos deprived of adequate water develop skin cracking and health problems from desiccation of their moisture-sensitive skin. Social management is also complex because the aggressive dominance interactions of hippos in confined spaces without adequate retreat space can result in serious injury. Well-resourced zoos with large, deep pools and carefully managed social groups can achieve reasonable hippo welfare outcomes.

What You Can Do

Visit only zoos with large, deep hippopotamus pools allowing full submersion and natural thermoregulatory behavior
Support wild hippo conservation programs addressing habitat loss and illegal hunting across sub-Saharan Africa
Advocate for zoo standards requiring minimum pool depth and surface area for hippopotamus exhibits
Donate to organizations monitoring wild hippo populations and protecting wetland habitat
Learn about hippo conservation status — populations have declined by 7-20% since the 1990s