Overview
At dusk, as the light fades and the air begins to cool, the hippopotamus leaves the water to feed. By day, it may appear almost motionless, with only its eyes, ears and nostrils visible above the surface. After dark, however, this immense herbivore can travel several kilometres across land in search of grass.
Hippos spend daylight hours in rivers, lakes and pools, where the water protects their skin from heat and dehydration. They are highly social in the water and may gather in groups containing females, calves and several males. Dominant bulls defend stretches of water, while feeding areas on land are generally not defended in the same way.
Despite their rounded appearance and largely plant-based diet, hippos are powerful, fast-moving animals that require considerable space and respect. Most dangerous encounters occur when a hippo feels threatened, is surprised at close range or finds its route back to the water blocked.
Behaviour & How to Identify
Look for an enormous barrel-shaped body, short legs, a broad head and a nearly hairless grey-brown hide. The eyes, ears and nostrils sit high on the head, allowing the hippo to remain mostly submerged while still seeing, hearing and breathing.
Hippos are semiaquatic but feed mainly on land. They leave the water around dusk and follow familiar paths to nearby grazing areas, returning before the heat of the next day. Their diet consists overwhelmingly of grass, although occasional consumption of other plant material, and rare cases of meat-eating, have been recorded.
A wide-open mouth is not always a yawn. Hippos use gaping displays to reveal their enormous canine teeth during threats, territorial disputes and confrontations. Their deep grunts, bellows and wheezing calls can travel both through the air and underwater.
Interesting facts
Their reddish skin secretion is not blood or sweat. Sometimes called “blood sweat”, it contains pigments that help absorb ultraviolet light and may also inhibit the growth of certain bacteria.
Hippos move along the bottom rather than swimming conventionally. They propel themselves by walking, running or bounding from the riverbed.
A hippo can open its mouth extraordinarily wide. The gape may approach 150 degrees and is used mainly for display and fighting rather than feeding.