The name hippopotamus comes from Greek and means river horse. Hippos, however, are not related to horses, but to pigs. Although hippos once ranged through Europe and Asia, they are now found only in the African interior and on game reserves. The pygmy hippo, which is the smallest species, occurs in West Africa, especially in or near rivers, lakes, and swamps. The common male hippo weighs up to 2,600 kg, but the pygmy hippo weighs only about 161-272 kg.
Common hippos are gregarious, live in herds, and are well adapted to life in the water.
By contrast, the pygmy hippo is a shy, solitary, forest dweller that is still hunted by the natives for its meat. When encountering people, it flees at once into the nearest river or swamp. Their life span is about 35 years, and they have adapted well to life in zoological gardens, a hopeful sign, as they are threatened with extinction in their natural habitat. The major threats to this species are deforestation and hunting.