Hippopotamus | WWF

The giants who dance under water

The hippopotamus is an enormous, semi-aquatic mammal with smooth, naked skin which lives in swampy areas, lakes, and rivers in Africa. Hippopotamus means ‘river horse’ in Greek, although the hippo is more closely related to a pig than a horse. It is the 3rd largest living land mammal, after the elephant and white rhino.

It has an inflated-looking body supported on short, relatively thin legs. The male weighs around 1,600-3,200 kg, and its height is about 140-165 cm whereas the female weighs 655-2,344 kg and is 130-145 cm high. It has a huge muzzle and eyes, nostrils, and small ears are placed high on head.

Its color is brown to gray-purple with pink underparts and creases; short bristles on head, back, and tail. It also has mucous glands which secrete an oily red fluid that protects skin from sunburn and drying, and perhaps infection.

Hippos do not have sebaceous or sweat glands, spending most of the day in water or mud to stay cool. At night they exit at the water at the same spot to graze on vegetation.

A bull hippo's canines can grow to 70cm (28 in) long, and their mouths can open over 1 m (4 ft) wide! Hippos are extremely graceful in the water, despite their clumsy appearance on land. Their specific gravity allows them to sink to the bottom of rivers and literally walk or run along the bottom. Adult hippos are able to stay underwater for as long as 5 minutes.

The hippos advertise their territory by dung-showering on middens: the bull backs up to heap, simultaneously urinates and defecates backward, paddling excrement with its tail.

Your chances of seeing one in the wild
Historically, hippos have been found throughout all of sub-saharan Africa, but most populations have been reduced or exterminated. Now largely confined to protected areas it still survives in many major rivers and swamps. Good places to see it would be almost any park and reserve with sizeable lakes and rivers bordered by grassland.

In 1995 it was listed on CITES appendix II. One subspecies, Hippopotamus amphibius tschadensis, is listed as vulnerable on the IUCN 1996 Redlist.
    © WWF / Fritz Pölking
© WWF / Fritz Pölking