The common hippopotamus (Hippopotamus amphibius), also called the river hippopotamus, is a species of semi-aquatic artiodactyl mammal in the family Hippopotamidae. They evolved during the Middle Pleistocene epoch, succeeding the earlier H. antiquus which was found throughout Europe prior to the ice ages. These mammals are indigenous to river basins throughout Africa, though their range has shrunk and fragmented in modern history due to poaching and habitat loss; they are currently considered Vulnerable by the International Union for Conservation of Nature. Hippos are among the largest land mammals currently alive. Their only close living relative is the pygmy hippopotamus (Choeropsis liberiensis).
There are five identified subspecies of common hippo:
- Hippopotamus amphibius amphibius, found between Gambia, Ethiopia, and Mozambique; historically lived in Egypt
- Hippopotamus amphibius kikobo, found in Kenya and Somalia
- Hippopotamus amphibius capensis, found in Zambia and South Africa
- Hippopotamus amphibius tschadensis, found between Chad and Niger
- Hippopotamus amphibius constrictus, found between the Democratic Republic of the Congo, Angola, and Namibia
