However, the two species of Hippo's closest relative is not the horse, but rather the pig. They stay close to water, but they are adapted to both life in the water and on land. They can spend up to 6 minutes underwater as well as reach land speeds up to 20 mph. Adults can reach lengths of 14 feet and 5 feet tall at the shoulder. They travel in herds of 5 to 30 animals, and although they have webbed feet to swim with, they often just walk along the bottom of the river.
Hippos have extensive adaptations for life in the water.
Apart from webbed feet, River Hippopotamuses have their eyes located atop their head so they can still see when the rest of their body is submerged. Their eye's and nostrils can seal shut whenever the hippo swims or dives. Their mucus glands secrete a pink colored liquid, to keep their skin from getting too dry as they graze along the bank. Hippos become adults at 4 or 5 years, and after mating there is a gestation of 7.5 months when the female normally have one young but occasionally twins. The mother nurses her young underwater and allows her young to sit on her back and sun itself as she floats on the water.