What Is a Hippopotamus?

Jennifer Long

There are two species of hippos, semi-aquatic mammals of the Hippopotamide family. Its Greek name, Hippopotamus amphibious, means river horse. Hippos are tied with the rhinoceros for the spot as the third-largest living land mammal.

Close-up of hippopotamus head and eye.
Close-up of hippopotamus head and eye.

A river, or common, hippopotamus is native to the sub-Saharan section of Africa. They remain in nearby lakes and rivers during day hours and graze on land during the evening hours when it is cooler. One hippo can eat 100 pounds (45.36 kg) of food in one day.

Hippos are considered the third-largest living land mammal.
Hippos are considered the third-largest living land mammal.

The common hippopotamus species tends to remain in large groups of 15 or more. Females are in greater number than males. A female can weigh about one and a half tons (1360.78 kg), while males can weigh an average of three tons (2721.55 kg). They have thin gray skin that closely resembles elephant skin. It secretes a pink oil substance to protect the hippo from sunburn and keep the skin from drying out.

Both male and female hippos are aggressive and territorial.
Both male and female hippos are aggressive and territorial.

A pygmy hippopotamus is smaller than the common species. It will only weigh about one quarter of the weight and half the height of the larger species. Their skin is similarly thin but is more brown or black in color. The pigmy hippo differs from the river hippo by its thinner bones and sloping spine. Although the pigmy species is also semi-aquatic, their habitat differs because they prefer the swampy forest regions of western African.

Hippopotamuses, regardless of the species, reproduce and give birth in the water. Calves are born after an eight month gestation period, and also nurse underwater. Females in the herd share babysitting and protection duties.

Male, and sometime female, hippos are aggressive and territorial. Although the hippopotamus will anger easily in the water with the herd, grazing is often done alone. While on land, the hippo does not act so aggressively.

A hippo will open its mouth very wide to expose its large teeth. Researchers believe this is an intimidation tactic the hippopotamus does try to scare off rivals or predators. Once engaged in a battle, the hippos ram into each other with their mouths wide open. They throw water with their lower jaws and head butt each other as well.

General populations of both species of the hippopotamus are in danger. The pigmy species has a significantly lower population count, but both are suffering. These animals are being hunted for their meat and their ivory teeth.

The common hippopotamus is native to the sub-Saharan section of Africa.
The common hippopotamus is native to the sub-Saharan section of Africa.

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Discussion Comments


@bear78-- Why are hippos shown so friendly and cute in toys and storybooks?

I too had a hippo toy when I was young. It was purple and very adorable. When I first saw a picture of a real hippo in school, I was very surprised. These animals are very large and not so cute in real life. I would definitely be intimidated if I was around one.

But I guess the trend of making cute toys for not so cute or friendly animals has been around for a while. Like Barnie the dinosaur and Pooh the bear!


@bear78-- That's a great point. People often talk about how aggressive hippootamuses are and how many people they attack and kill annually. But few people talk about how people attack these animals, and hunt them for their meat and teeth. It's very natural for them to be aggressive in these circumstances. They are just trying to protect themselves and their young.


I had several hippo toys as a child and I always loved saying their name. Hippos are one of my favorite animals and I've always found the toys adorable. I must admit though, in the pics where they've opened their mouths, they look very frightening. I'm sad that they are under the risk of being endangered though. The fact that they are being hunted explains why they are aggressive. People just need to leave them alone.

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