Hippopotamus, or hippos, are large African mammals that like to spend a lot of time in the water. The common hippopotamus and the pygmy hippopotamus are the only two species of hippo that exist today. After the elephant and the rhinoceros the hippopotamus is the third largest land mammal weighing in at 1,500 kilograms.
Hippos may look like they are closely related to either buffaloes or cows but their closest living relative is in fact from the cetacean family which include whales and porpoises.
Hippos are mainly herbivores, however they are extremely aggressive. If they feel threatened or territorial a hippopotamus will not hesitate to attack. Their mass and huge tusks put them at an advantage in these fights. As well as this, hippos are extremely fast. They can run up to 30km/h over short distances and through water.