Behavior
Hippos spend most of their days wallowing in the water, or the mud, with the other members of their pod. The water serves to keep their body temperature down, and to keep their skin from drying out. With the exception of eating, most of hippopotamuses' lives —from childbirth, fighting with other hippos, to reproduction— occur in the water. Hippos leave the water at dusk and travel inland, sometimes up to 8 kilometers (5 mi), to graze on short grass, their main source of food. They spend four to five hours grazing and can consume 68 kilograms (150 lb) of grass each night. Like almost any herbivore, they will consume many other plants if presented with them, but their diet in nature consists almost entirely of grass, with only minimal consumption of aquatic plants. Hippos have (rarely) been filmed eating carrion, usually close 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 caused by aberrant behavior or nutritional stress.
The diet of hippos consists mostly of terrestrial grasses, even though they spend most of their time in the water. Most of their defecation occurs in the water, creating allochthonous deposits of organic matter along the river beds. These deposits have an unclear ecological function. Because of their size and their habit of taking the same paths to feed, hippos can have a significant impact on the land they walk across, both by keeping the land clear of vegetation and depressing the ground. Over prolonged periods hippos can divert the paths of swamps and channels.
Adult hippos move at speeds up to 8 km/h (5 mph) in water. Adult hippos typically resurface to breathe every three to five minutes. The young have to breathe every two to three minutes. The process of surfacing and breathing is automatic, and even a hippo sleeping underwater will rise and breathe without waking. A hippo closes its nostrils when it submerges into the water. As with fish and turtles on a coral reef, hippos occasionally visit cleaning stations and signal, by openning their mouth wide, their readiness for being cleaned of parasites by certain species of fish. This situation is an example of mutualism in which the hippo benefits from the cleansing, while the fish receive food.
Read more about this topic: Hippopotamus
Famous quotes containing the word behavior:
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