The hippopotamus, a massive, semi-aquatic mammal native to sub-Saharan Africa, spends most of its day submerged in water, which serves to protect its sensitive skin from the intense sun. Weighing several tons, this animal requires a substantial amount of energy. While they appear to live entirely in the river or lake, their diet is almost exclusively tied to the land surrounding their aquatic homes.
The Primary Diet: Terrestrial Grazing
The bulk of a hippo’s sustenance comes from grazing on short, sweet grasses found in the surrounding savannahs and floodplains. Despite their enormous size, hippos are strict herbivores and do not use their massive incisors and canines for feeding. These long, sharp teeth function solely as weapons for defense and displays of dominance.
Instead, the hippo relies on its broad, muscular lips, which can be up to 50 centimeters wide, to crop the vegetation. Once the grass is cropped, the hippo uses its powerful back molars to grind the fibrous material down before swallowing. Although they spend nearly all their day in the water, aquatic plants make up a remarkably small portion of their natural diet.
Nocturnal Feeding Habits
The hippo’s decision to feed away from the water is dictated by the unforgiving African climate. They emerge from the water just after dusk to begin their nightly foraging, a routine that avoids the intense daytime heat. This nocturnal behavior is necessary to prevent their sensitive skin from drying out and to protect it from sunburn.
A typical grazing session lasts between four and six hours, during which a hippo will follow familiar paths that often lead several miles away from the water source. They have been known to travel up to 10 kilometers in a single night to reach the best grazing spots. Hippos must return to the water before dawn, often seeking the nearest available pool if they have traveled too far from their home territory.
The Surprising Exceptions to the Herbivore Rule
While the hippo is classified as a herbivore, observations have documented behaviors that challenge this traditional categorization. In addition to their primary grass diet, hippos occasionally consume fallen wild fruits when available. They may also consume aquatic plants, particularly during periods when terrestrial grasses are scarce due to drought.
More surprisingly, hippos have been observed consuming meat, either by scavenging carrion or, in rare instances, eating the carcasses of other animals. Scientists suggest this opportunistic carnivory may be linked to nutritional deficiencies or environmental stress. The hippo’s digestive system is not adapted for regular meat consumption, supporting the idea that these incidents are exceptions rather than a fundamental shift in their feeding habits.
How Much Do Hippos Need to Eat?
Despite their massive body size, hippos consume a surprisingly small quantity of food relative to other large land mammals. An adult hippo typically eats around 40 to 50 kilograms of grass per night, which amounts to only about 1 to 1.5% of its body weight daily. This low intake for such a large animal is possible because hippos have an unusually low metabolic rate.
Their largely sedentary lifestyle, spending most of the day submerged in water, significantly reduces their energy expenditure. The digestive process is also highly efficient, characterized by a multi-chambered stomach that functions as a non-ruminant foregut fermenter. This system allows for a long retention time for the food, which helps the hippo extract the maximum amount of nutrients from the fibrous grasses they consume.