The hippopotamus is the second-largest land mammal, weighing up to 8,000 pounds, with the elephant being the largest.
Hippos have extensive adaptations for life in the water.
They have webbed feet and their eyes are located on top of their head so they can still see when the rest of their body is submerged. Their ears and nostrils can seal shut whenever the hippo swims or dives. It normally stays underwater for about six minutes but it can stay submerged for up to 20 minutes. Glands in their skin secrete a pink liquid, to keep their skin from getting too dry as they graze along the bank. Their barrel-like appearance, short legs and belly only inches from the ground, does not inhibit them from moving quickly on land when necessary.