Why do hippopotamuses spend much of the day in rivers, lakes, and swamps?

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A hippopotamus stands at the edge of a watering hole, with several other hippos partially submerged in the water, surrounded by green vegetation in Botswana, Africa. — hippopotamus The word *hippopotamus* is Greek for “river horse,” which reflects their behavior: they are often seen basking on the banks or sleeping in the waters of rivers, lakes, and swamps across Africa. They favor shallow areas where they can sleep half-submerged, though these places can become quite crowded—as many as 150 hippos may use one pool in the dry season.

Hippopotamuses spend much of their day in rivers, lakes, and swamps primarily because they are well adapted to aquatic life and require these environments to regulate their physiology.12

Because hippos do not sweat, they must retreat to the water to keep cool. Furthermore, they lose water rapidly through their skin and can quickly become dehydrated if they do not take periodic dips in the water. While they are often seen basking in the sun, they rely on these aquatic environments to maintain their health. Additionally, their bodies are dense enough to allow them to walk underwater, where they can remain submerged for up to five minutes at a time.12