Hippopotamus

The hippopotamus is a large semi-aquatic mammal from sub-Saharan Africa. Its name comes from Ancient Greek words meaning river horse. After elephants and rhinoceroses it is the next largest land mammal, with bulls averaging about 1.5 tonnes and cows about 1.3 tonnes.

Hippos spend the day cooling off in rivers, lakes, mangrove swamps or mud, and come out at dusk to graze on grass. Despite looking like big pigs, their closest living relatives are whales and dolphins. They are also counted among the most dangerous animals in the world, and habitat loss and poaching for meat and ivory threaten them.

Life in the water

Each territorial bull guards a stretch of water and a group of five to thirty cows and calves. Mating and birth both happen in the water. The animals rest close together there, yet when they graze on land they usually feed alone, walking out at night. The card on the globe adds that a hippo can open its mouth nearly 150 degrees and that its skin oozes a reddish fluid that helps protect it from the sun.

Relatives and risks

The hippo family has only two living members, the common hippo and the much smaller pygmy hippo. Their closest relatives are cetaceans, the group of whales, dolphins and porpoises, and the two lines split about 55 million years ago. Hippos are aggressive and unpredictable, so people should keep a long distance. They are listed as Vulnerable, which means the wild population needs protection from habitat loss and hunting.

On the globe

Find the hippo near Nyerere National Park in Tanzania; the card notes its huge mouth and reddish skin fluid.