SKIMMING

HIPPOS

AFRICA'S GIANT WATER DWELLERS

Native only to Africa, the hippopotamus comes in two very distinct species: the massive common hippo and its smaller, endangered cousin, the pygmy hippo. While the name "hippopotamus" in ancient Greek means "river horse," their closest mammalian relatives are actually whales and dolphins.

To protect their thin-skinned hides from dehydration, common hippos cool off in rivers and lakes for up to 16 hours a day and can stay fully submerged for fives minutes without breathing. At dusk, they go on land to graze on short grasses and reeds, consuming about 80 pounds of food in one evening. In the event of a shortage, a hippo can store two days' worth of food in its stomach and go up to three weeks without eating.

Unlike pygmy hippos, which only weigh a few hundred pounds, common hippos are one of the largest land mammals, with males weighing upwards of four tons. Only elephants and white rhinos are known to exceed them in size. And while common hippos are generally seen as non-violent because they lack predators, they do engage in territorial standoffs with one another and can inflict mortal injuries with their huge tusks.

Image credit: PB_images/Thinkstock