Hippos eat plant foods, particularly grasses, shoots, leaves, reeds, flowers, stems and bark. They've been known to scavenge, though they are herbivores, and their digestive systems haven't evolved to eat meat. Biologists believe that mostly sick or malnourished hippos eat meat.
The pygmy hippopotamus is classified as a vegetarian. This animal not only eats grass and shoots, but it also consumes ferns, herbs, semi-aquatic plants and fruit. Interestingly, the pygmy hippopotamus has a stomach with multiple chambers, like a cow. However, its digestive system does not work in the same way as a cow's or other true ruminant's digestive system.
Hippos feed at night. The hippopotamus comes out of its usual body of water to eat, but it always tries to stay as close to its home as possible. However, if food is scarce, it is capable of traveling a few miles to find another food source. The hippopotamus uses its wide lips to tear up grasses and soften them before swallowing; it doesn't chew with its teeth. Because grasses and other such vegetation are low in nutrients, the hippo needs to eat a great deal to receive a good amount of nutrition. Hippos have been known to eat almost 90 pounds of food every night.