Hippos can be [blank_start]found[blank_end] in both savannah and forest areas. Proper habitat [blank_start]requires[blank_end] enough water to [blank_start]submerge[blank_end] in and grass nearby. Larger densities of the animals inhabit quiet waters with mostly firm, smooth sloping beaches. Males may be found in very small number in rapid waters in rocky gorges. With the exception of eating, most of hippopotamuses' lives – from [blank_start]fighting[blank_end] with other hippos, mating, to parturition – occurs in the water. Hippos [blank_start]leave[blank_end] the water at dusk and travel inland, sometimes up to 10 km (6 mi) to graze on short grasses, their main source of food. They spend four to five hours grazing and can consume 68 kg (150 lb) of grass each night. Like almost any herbivore, they consume other plants if presented with them, but their diet in nature consists almost entirely of grass, with only minimal consumption of aquatic plants. Hippos are [blank_start]born[blank_end] with sterile intestines, and require bacteria obtained from their mothers' feces to digest vegetation. Hippos have (rarely) been filmed eating carrion, usually [blank_start]close[blank_end] to the water. There are other reports of meat-eating, and even cannibalism and predation. The stomach anatomy of a hippo is not suited to carnivory, and meat-eating is likely [blank_start]caused[blank_end] by aberrant behaviour