Hippopotamuses are large, semi-aquatic mammals native to sub-Saharan Africa. They are among the largest land mammals, with adult males weighing around 1,480 kg and females around 1,365 kg. Hippos spend a significant portion of their day submerged in water, which serves to protect their sensitive skin from the harsh sun. Their unique lifestyle, balancing extensive time in aquatic environments with terrestrial foraging, often sparks curiosity about their diet. Understanding what hippos consume is important to appreciate their distinct adaptations and their role within the ecosystems they inhabit.
The Staple: Grass
Hippos are predominantly herbivores. Their primary food source is short grasses found in savanna landscapes. An adult hippo can consume a substantial amount of grass, typically around 40 to 50 kilograms (88 to 110 pounds) per night. This intake represents a relatively small percentage of their body weight, about 1 to 1.5%.
Their specialized teeth are well-suited for this grazing diet. Hippos use their flattened, horny lips to grasp and pull grasses. While their large canine tusks, which can grow up to 50 cm, are primarily for defense and territorial displays, their molars are designed for grinding plant material.
These broad, flat molars have complex enamel folds that aid in efficiently breaking down tough fibrous vegetation. Despite their massive size, hippos are efficient grazers, impacting the landscape by keeping areas clear of vegetation. Their grazing activities can also promote stouter, more leafy grass growth in frequently grazed areas, which is beneficial for their diet.
Beyond the Usual Diet
While hippos are classified as herbivores, occasional observations have led to questions about the true breadth of their diet. Hippos do not typically eat meat; their digestive system is not adapted for it. Their physiology is set up for herbivory.
Instances of hippos consuming carrion, such as animal carcasses, are extremely rare and are generally believed to occur when there are severe nutritional deficiencies or when their regular food sources are exceptionally scarce. Documented cases of hippos eating meat, or even engaging in cannibalism, are considered atypical behaviors.
These rare occurrences do not alter their fundamental classification as herbivores. Besides grasses, hippos might also infrequently consume other plant matter like wild fruits or aquatic vegetation, though these make up a very small portion of their overall intake.
Feeding Habits and Environment
Hippos exhibit distinct feeding habits influenced by their semi-aquatic lifestyle. They spend most of the day submerged in water, using it as a refuge from the sun and a place for social interaction. As dusk approaches, hippos leave the water to forage on land, typically grazing for four to six hours throughout the night. This nocturnal feeding habit protects their sensitive skin from the hot African sun.
Hippos can travel several kilometers from their water bodies in search of suitable grazing areas, sometimes covering 3 to 8 kilometers (1.9 to 5 miles) in a single night. They often prefer patches of short grasses, sometimes referred to as “hippo lawns,” found close to water sources, but will venture further if necessary.
Despite often resting in groups during the day, grazing is generally a solitary activity for individual hippos, and they typically do not display territorial behavior on land while feeding. They use their keen sense of smell and hearing to locate food. The availability of both water for daily refuge and land for nocturnal grazing is important for their survival, directly linking their habitat to their feeding strategy. They return to the water by dawn, often using the same entry points, completing their cycle of foraging and resting.