The hippopotamus is a megaherbivore of sub-Saharan Africa, the third-largest land mammal after the elephant and certain rhinoceros species. These semi-aquatic animals spend their days submerged in rivers, lakes, and swamps to stay cool, emerging at night to graze. Despite their herbivorous diet, hippos are famously aggressive and territorial, possessing massive jaws and powerful canine tusks. While hippos do have predators, the risk is not evenly distributed; the danger is focused almost entirely on juvenile hippos, while healthy adults are rarely threatened.
The Age Divide Vulnerability of Hippo Calves
The single greatest factor determining a hippo’s risk of predation is its age. Calves are born weighing around 50 kilograms (110 pounds) and are instantly vulnerable due to their small size and dependence. Birth and nursing often occur in the water, exposing the newborn to aquatic threats.
A calf stays close to its mother, often resting on her back for safety, but this protection is not absolute. High vulnerability lasts until the calf is about one to two years old, well past the six to eight months it takes to wean. Young hippos are also at risk during territorial disputes between aggressive adult males.
Predation opportunities increase when the young hippo is separated from the mother or the main pod, especially when water sources are limited during dry seasons. The most vulnerable moments occur when the pod leaves the water to graze on land at night. A calf’s inability to keep pace or defend itself makes it an easier target for terrestrial predators.
Identifying the Primary Threats
The list of animals that prey on hippos is short, with successful hunts aimed squarely at the vulnerable calf population.
The Nile crocodile is the most consistent threat, often targeting young hippos in the water or near the riverbank. Crocodiles utilize stealth and aquatic ambush tactics. While they avoid challenging a full-grown hippo, they will occasionally prey on half-grown, sick, or injured individuals.
Lions are the primary terrestrial threat. They operate in large prides, relying on teamwork and ambush to isolate a calf or a weakened individual grazing on land at night. A coordinated attack by a large pride is one of the only documented ways an adult hippo is sometimes successfully taken, though this is uncommon.
Opportunistic pack hunters like spotted hyenas and African wild dogs also pose a significant threat to the young. Hyenas are known to prey on very young, sick, or injured hippos separated from the protective pod. The sheer number of a pack can overwhelm a single mother’s defense, especially if the attack occurs far from the water.
The Hippo’s Natural Defenses
Healthy adult hippos are formidable animals whose natural defenses make them virtually predator-proof. An adult male can weigh up to 3,500 kilograms (7,700 pounds), a massive bulk that deters most predators. This immense size is paired with a thick hide, up to 5 centimeters (2 inches) deep on the flanks, offering protection against bites and scratches.
The hippo’s aggression is a major defensive mechanism; they are intensely territorial and will charge any perceived threat. Their jaws open incredibly wide and are armed with sharp lower canines that can grow up to 50 centimeters (20 inches) long, capable of crushing bone. They frequently use this power to displace or kill crocodiles in their waterways.
Water is the hippo’s sanctuary, providing safety from land predators like lions and hyenas. Despite their bulk, hippos are agile and fast swimmers, using their aquatic advantage to outmaneuver threats. When threatened on land, they quickly retreat to the water, where their size and formidable jaws make them difficult targets.