Males maintain their territories for four to eight years and during this time hold the exclusive mating rights to resident females. Non-territorial males do not breed. This name suits the hippo, which spends its days in or near water. At night, aquatic groups of hippos break up, individuals go to shore, and females and their infants stay together. Hippos follow onshore trails marked with dung piles to grazing fields, feed for about five to eight hours, then return to the water before dawn or early in the morning.
Hippos are excellent swimmers but prefer to amble along the bottom of slow-moving or stagnant water.
An adult hippo can stay under water for up to five minutes. Since hippos are such large animals they greatly affect their habitats. In water, hippos deposit tons of excrement, which fertilizes plants and feeds animals such as fish. On land, however, hippos are not as beneficial. They overgraze grass fields and their big feet trample the wet ground around lakes and rivers causing erosion.