What Do Hippos Eat? Night Grazing and Hippo Diet Myths

What exactly do hippos eat?

The wild hippo’s diet is almost entirely made up of grasses, especially short, fresh grasses on floodplains, riverbanks and open grassland. Hippos prefer creeping and short species over tall, coarse grass. They eat very little of the reeds and water plants in the rivers and lakes where they rest, despite spending so much time there.

In some places, and particularly in dry seasons when grass is scarce, hippos also eat other low plants, fallen fruit and crops. In zoos, hippos eat hay, grass and vegetables. But the natural pattern is simple: hippos are grazers, closer in diet to cattle or zebras than to most other big river animals.

How do hippos graze?

A hippo does not bite grass with its front teeth. Its long canines and incisors are weapons used in fights. Instead, it grips the grass with its broad, hard lips, which can be about 50 cm (20 in) wide, and tears it off with a swing of the head. The back teeth then grind the grass.

Hippos usually feed alone, even though they rest in close groups during the day. Each animal follows well-worn paths from the water to its grazing grounds. Over years, these paths become deep trails, and the constant grazing keeps the grass close-cropped, creating “hippo lawns” that other grazing animals also use.

How far do hippos travel to feed?

Most hippos walk about 3–5 km (2–3 mi) from the water each night, and sometimes much farther. During droughts, when grass near rivers has been eaten down, hippos may travel well over 5 km (3 mi) to find food, and they can raid crops along the way. This is one reason hippos come into conflict with farmers.

Feeding at night is linked to the hippo’s skin. Hippos lose water through their skin quickly and can overheat or burn in strong sun, so they rest in water by day and feed in the cool darkness. Their skin produces a red secretion that acts like a sunscreen, explained in Do hippos sweat blood?

How much do hippos eat?

An adult hippo eats roughly 35–40 kg (75–90 lb) of grass a night. That sounds like a lot, but it is modest for an animal that weighs around 1.5 tonnes. Hippos save energy by resting in water during the day, where the water supports their great weight and keeps them cool.

Hippos also digest their food slowly. Their stomach has several chambers, and food stays in the gut for a long time, letting microbes break down tough plant material. Hippos are sometimes called pseudoruminants: like cattle, they rely on fermentation in a complex stomach, but unlike cattle they do not chew the cud.

Do hippos ever eat meat?

Occasionally, yes, and it surprised biologists. Hippos have been seen feeding on carcasses, including other hippos, wildebeest and impala, and in rare cases attacking and eating other animals. A 2016 review of these reports concluded that meat eating is more widespread among hippos than once thought, but still unusual.

Hippos are not built for it. Their stomachs are adapted to digesting grass, not meat, and scientists suspect that meat eating happens when animals are stressed, short of food or lacking certain nutrients. Eating carcasses can also be risky: it may help spread diseases such as anthrax, which has caused mass deaths in some hippo populations.

Why is hippo dung important for rivers?

What hippos eat on land ends up in the water. After grazing all night, hippos spend the day in rivers and lakes, where they release large amounts of dung. In this way they carry nutrients from grassland into the water, feeding insects, fish and other river life. Fish are often seen gathering around resting hippos.

There is a downside too. Where many hippos crowd into small pools during the dry season, so much dung can build up that it uses up the oxygen in the water and fish die. Scientists see hippos as “ecosystem engineers” whose eating and dung shape whole river systems.

Hippo diet myths

Myth: hippos eat people. Hippos do not hunt or eat people. Their attacks are defensive, triggered by threats to their territory, their calves or their route back to water. Read more in Why are hippos so dangerous?

Myth: hippos eat fish. Hippos do not catch or eat fish. Fish feed on their dung and pick parasites and dead skin off their bodies.

Myth: hippos feed in the water. Although they live in water, hippos feed almost entirely on land.

What do pygmy hippos eat?

The smaller pygmy hippopotamus of West Africa has a broader diet. Living in forests, it browses on ferns, broad-leaved plants and fallen fruit as well as grasses, feeding mainly at night along forest trails.