Illustration of an African river ecosystem, showing the impact of the herbivorous mammal the hippopotamus (Hippopotamus amphibius). Their grazing creates areas that allow other animals to graze such as antelopes. The waterways and rivers they inhabit also benefit from the faeces they deposit (lower right). The nutrients from the plant material in their faeces support various food chains (circular insets at lower left), including microbes, plankton and aquatic insects and crustaceans. These are eaten by birds (one at upper left) and by fish, which are in turn caught by birds of prey, humans, and predatory reptiles.