The hippopotamus, defined by its immense size and fierce territoriality, stands as one of Africa’s most formidable large mammals. Weighing up to 4,000 pounds and possessing a thick hide several inches deep, an adult hippo presents a massive defensive challenge to any potential attacker. Its powerful jaws, armed with canine tusks that can grow over a foot long, are used as weapons against rivals and threats. This combination of sheer bulk, natural armor, and aggression means that a healthy, mature hippo has virtually no sustained natural predators. Predation is rare, occurring only when specific conditions align to exploit a vulnerability in its defenses.
The Dominant Aquatic Threat: Nile Crocodiles
The Nile crocodile is the only predator that consistently engages with hippos, a dynamic born from their shared aquatic habitat. Crocodiles avoid challenging healthy adult hippos, focusing instead on newborn and juvenile hippos, which lack the size and experience of their mothers. The water that provides sanctuary for the adult hippo becomes a hunting ground when a calf is momentarily separated from the protective pod.
Crocodiles utilize the water’s murky visibility for classic ambush tactics, striking with explosive speed from below the surface. A calf that strays from its mother’s immediate proximity risks being seized and dragged away before the adult can intervene. While adult hippos frequently chase, bite, and even kill crocodiles that threaten the pod, the risk remains a constant for the young. The aquatic environment shifts the advantage in favor of the crocodile’s stealth and powerful bite force.
Terrestrial Hunters: Group Tactics of Lions and Hyenas
On land, the hippo’s primary threats are the African lion and, less frequently, the spotted hyena. Successful hunts are highly dependent on group cooperation. Lions, especially large prides, occasionally target hippos as they leave the water at night to graze. This nocturnal timing is crucial, as the hippo is away from its defensive aquatic element and must rely solely on its speed and aggression.
The lions’ strategy involves overwhelming the animal through coordinated attack, often seeking to separate one individual from a group. They typically focus on the hippo’s legs and flanks to immobilize it, using their collective weight and strength to bring the massive animal to the ground. Hyenas operate similarly, relying on the sheer numbers of a large clan to harass and wear down a target. However, hyenas are primarily opportunistic scavengers, and any successful attack on a hippo is usually only attempted against an already compromised, injured, or undersized individual.
Conditions That Lower a Hippo’s Defenses
The most common factor that lowers defenses is age, as calves are the easiest and most frequently targeted prey for both crocodiles and lions. A calf’s relatively small size and lack of defensive tusks make it a viable meal, provided its mother can be distracted or avoided. The protective social structure of the hippo pod, or “bloat,” is a major deterrent, but an isolated individual is immediately at higher risk.
Any hippo that becomes separated from the group, perhaps due to a territorial dispute or during a long overland trek, loses the collective intimidation factor of the pod. Environmental stressors like severe drought are another major condition that increases vulnerability across all age groups. Shrinking water sources force hippos to travel greater distances across land in search of new pools, exposing them to terrestrial predators during daylight hours. A hippo weakened by lack of forage or dehydration becomes an appealing, lower-risk target for a large pride of lions or a clan of hyenas.