Their name comes from ancient Greece and means water horses or river horses. The closest relatives of hippos are whales, swallows, dolphins. They are the third largest Earth mammals just after elephants and white rhinoceros. Adult male measures up to 360 cm, height (withers) 165 cm weighs over 3 tons. The hippopotamus has a cylindrical body shape that is long, rounded and with a bulky abdomen. It has strong and low limbs and fingers (4) are ended with blunt hooves with a floating membrane. The hippopotamus has a very heavy skeleton without air cavities and it facilitates diving and allows walking down the bottom. Ears, eyes and nostrils are placed very high on the head because of their stay in the water. Ears and nostrils are equipped with valves and close when immersed. The skin of the hippo is very thick and below it is a 5 cm layer of fat. The skin is very sensitive and easily cracks in dry conditions.

Originally, they lived across Africa from the Nile Delta to Cape, but they were destroyed in the Nile Delta in ancient times, and Capek, Nubia, and Northern Judah disappeared during the 19th century. Today they live in much of Sub-Saharan Africa.

The hippopotamus is a social creature and lives in a group (up to 150), but usually between 10 and 20. In a smaller group is male, female and chicks. In a big group, there are several males that have a strict hierarchy. Under water, it lasts for a touch of 3 to 5 minutes, but if necessary up to 25 minutes. The hippopotamus, despite its body structure, can climb (climbing from the water on a steep bank). It will develop a speed of up to 30 km / h (running only in distress). Live rhizomes and roots from the bottom (lotus) or floating plants, but most food is at night grazing on land.

They spend 16 hours in the water, because they can not swim, so spend most of their time in shallow water by the shore. They are among the most aggressive animals in the world and sometimes attack humans. In Africa, about 500 people kill each year.