Hippopotamus is the third largest land mammal after elephants and rhinoceroses. It is huge and clumsy, with a body length of 350-450 cm, a tail length of about 56 cm and a weight of 3000-3500 kg. But it is short, its limbs are extremely short, and its shoulder height is only 140- 165cm, which is less than half the height of an elephant. Its head is very thick and its mouth is very big, which is bigger than the mouth of any animal on land and can be opened at a 90-degree angle. The teeth in the mouth are also very big. Front teeth and canine teeth are sharp teeth and are the main weapons of attack. The lower incisors do not grow upward, but extend parallel to the front like a shovel, 60-70 cm long and weighing 2-3 kg. The length of canine teeth is also about 75 cm. Eyes, nostrils, ear shells, etc. Are born at the top of the face, almost on the same plane.