Hippopotamus amphibius, or hippopotamus, is a large herbivorous mammal in sub Saharan Africa. It is one of the only two species in hippopotamus family. The other is the Dwarf Hippopotamus (Choeropsis liberiensis or Hexaprotodon liberiensis). The name comes from "Hippo" in ancient Greek. After elephants and rhinoceroses, hippopotamus is the most common mammal in the third continent, and also the heaviest D animal in existence. Although similar to pigs and other land hoofed animals, hippopotamales are closely related to cetaceans (whales, dolphins, etc.), which they separated from about 55 million years ago. The common ancestor of whales and hippos separated from other toed ungulates about 60 million years ago. The earliest known hippopotamus fossil belongs to the genus pot of Kenya in Africa, and its history can be traced back to 16 million years ago.

Common hippos can be identified by their barrel shaped trunk, open mouth with canine teeth, almost hairless body, columnar legs and large size. The average weight of adult men and women is 1500 kg (3300 lb) and 1300 kg (2900 lb), respectively, making them the largest land mammal after three kinds of elephants, white rhinoceros and Indian rhinoceros. Despite its strong shape and short legs, it can still travel at a speed of 30 km / h (19 mph) in a short distance. Hippopotamus is a highly aggressive and unpredictable animal and is listed as one of the most dangerous animals in Africa. However, they are still threatened by habitat loss and poaching of meat and ivory canines.

Common hippos are semi aquatic, inhabiting rivers, lakes and mangrove swamps, where bulls host a river and are made up of five to thirty females and young females. During the day, they stay cool in water or mud; reproduction and childbirth occur in water. They appear at dusk and graze on the grass. Although hippos are close to each other in the water, grazing is a separate activity and hippos do not belong to the territory on land.