why does hippotamos soak on a river?

Answer 1

it keeps them cool..

Answer 2

You know I am not an expert on hippopotomi, but I've seen a few wildlife documentaries on them because I couldn't sleep and I thought it would cause me to fall asleep. They play an important role in the river ecosystem. Small fish-like animals, their waste even contributes to the nutrient make up of the river bottom. Parasites can get in their skin when they are on land all night eating grass and the water all day just feels so good for those little fish thingies to pick them out of their skin. Hippos are very territorial and greedy and when they find water they stand guard and will not leave their jealously and closely guarded water all day long until they risk leaving it at night to eat grass.

EDIT: Also it's safer from predators. Lions and hyenas won't go into water teeming with crocodiles, but crocodiles leave adult hippos alone because they are too large and immensily strong to kill.

EDIT#2: Oh yeah, it's also much cooler. The person below me. Their sweat is pink actually I believe I heard. Their dermal physiology does require water to keep cool in the hot African sun more so than other animals with different adaptations to keep cool then they have.

Answer 3

Because it can? They are large animals, and the water helps support their weight, also their skin in sensitive to the sun and being submerged give them protection. But elephants are large too, and they spend most of their time on land, so I'll go with my first answer, "because they can", or more specifically, there was a niche in the environment they evolved to fit.

Answer 4

A hippopotamus needs to cool itself by being in water.

Answer 5

Probable to support that enormous weight.

Answer 6

I'd say the same reason we do in the tub