These giant plant-eaters are actually related to camels, pigs, and deer. However, unlike their relatives, hippopotami have huge mouths and teeth. A bull hippo's canines can grow to 28 inches (71 cm) long, and they have mouths capable of opening to the extraordinary four feet (1.2 m)! We all know that throughout the day hippos like swimming and relaxing in the water. But do you know that hippo's night life begins a few hours after sunset, when it gets out of the water and starts looking for food? In fact, these huge animals can wander up to 6 miles (10 km) away from water and can eat as much as 100 pounds (45kgs) of vegetation a night.