The hippopotamus is semi-aquatic, inhabiting rivers, lakes and mangrove swamps, where territorial bulls preside over a stretch of river and groups of 5 to 30 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 grass. While hippopotamuses rest near each other in the water, grazing is a solitary activity and hippos are not territorial on land. Hippos are recognizable by their barrel-shaped torso, enormous mouth and teeth, nearly hairless body, stubby legs and tremendous size. It is the third largest type of land mammal by weight (between 1½ and 3 tons). The only heavier species on average are the white and Indian rhinoceroses, typically 1½ to 3½ tons, and the elephants, typically weighing 3 to 9 tons. The hippopotamus is one of the largest quadrupeds and, despite its stocky shape and short legs, it can easily outrun a human. Hippos have been clocked at 30 km/h (19 mph) over short distances. The hippopotamus is one of the most aggressive creatures in the world and is often regarded as one of the most dangerous animals in Africa. They are still threatened by habitat loss and poaching for their meat and ivory canine teeth. There is also a colony of non-zoo hippos in Colombia introduced by Pablo Escobar.
- hippos do not make great pets
- hippos can open their moves very wide
- hippos can stay under water for a long time