Why Don't Hippopotami Drown in the River?

Hippopotamus is a kind of mammal. Since they live at the bottom of rivers and lakes in tropical Africa for a long time, hippopotamus get used to the life in water. A large hippopotamus may weigh 3,000-4,000 kilogrammes. With his thick fat, a hippopotamus can easily float on the water surface. It also has an excellent diving capability. It can shut its ears and nostrils so that the water will not enter. When encounting enemies, a hippopotamus may dive a few hundred metres at a stretch.

If a hippopotamus doesn't stay under the water, its skin will become dry and chapped after a certain period of time. So, the hippopotamus always remains submerged in the daytime. At night when it becomes cool, the animal goes to the land to sleep or look for food.