The name hippopotamus, often shortened to 'hippo', is derived from the Greek word for 'river horse'. It is an apt description of the pygmy hippo, a reclusive and nocturnal mammal that spends much of its time in rivers or swamps. Being semi-aquatic, mating and giving birth may occur in water or on land.
Pygmy hippos are one of only two surviving species of the hippopotamidae family, the other being the much larger hippo. Adult pygmy hippopotamuses can reach a body length of between 1.4 and 1.6 metres, and can weigh between 245 and 275 kilogrammes.