The common hippopotamus (Hippopotamus amphibius), or hippo, is a large, mostly herbivorous, semiaquatic mammal native to sub-Saharan Africa. Common hippos are recognizable by their barrel-shaped torsos, wide-opening mouths revealing large canine tusks, nearly hairless bodies, columnar legs and large size; adults average 1,500 kg (3,310 lb) and 1,300 kg (2,870 lb) for males and females respectively. Despite its stocky shape and short legs, it is capable of running 30 km/h (19 mph) over short distances.
The common hippopotamus inhabits rivers, lakes and mangrove swamps, where territorial bulls preside over a stretch of river and groups of five to thirty females and young. During the day, they remain cool by staying in the water or mud; reproduction and childbirth both occur in water. They emerge at dusk to graze on grasses. While hippopotamuses rest near each other in the water, grazing is a solitary activity and hippos are not territorial on land. The hippopotamus is among the most dangerous animals in the world as it is highly aggressive and unpredictable. They are threatened by habitat loss and poaching for their meat and ivory canine teeth.