A River Pig?
Centuries ago, Greeks observed a huge, wallowing creature that appeared to sweat blood. They called it a hippopotamus, or river horse, a misleading name because it behaves more like a pig than a horse! And it does not sweat blood but secretes a sticky pink oil which helps to moisturize its skin and to act as a sunscreen in the hot African sun.

The two modern species of hippos, found only in Africa, differ in size, diet, and habitat. Little is known about the secretive pygmy hippo, Choeropsis liberiensis, which inhabits rain forests and swamps. Much more is known about the large common hippo, which is found in rivers and lakes.

Hungry Hippos
When a hippo is ready to eat, it lumbers out of the water at dusk when most other animals are settling in for the night. A hungry hippopotamus can wander up to ten km(six miles) away from its waterhole to look for a suitable meal. Hippos are herbivores, consuming 35 to 45 kg (80-100 lb.) of vegetation a night. They spend five to six hours during the cool evening grazing on short grasses before returning to the water at dawn, where they spend the rest of their day.

Life In The Water
The common hippo is amphibious, having special adaptations for life in the water. With its nostrils, eyes, and ears located on the top of its head, the hippo can stay safely underwater, able to breathe, see, and hear the world above without exposing its body. If it submerges, it closes its nostrils, and presses its ears flat against its head to prevent water from entering.

Buoyancy allows this bulky animal to move easily through the water. It uses its short legs to propel itself forward, or to walk along the bottom in shallow waters. Hippos give birth in the water, so in order to reach the surface for its first breath, a newborn must be able to swim the moment it is born. As an adult, a hippo can stay underwater for five to six minutes. When it surfaces to breathe, it does so with loud snorts and hisses to expel stale air from its lungs through its nostrils.

And The Winner Is...
Hippopotami live in groups of fifteen or more individuals consisting mainly of females, their young, a dominant adult male, and a few inferior males. Once the lead bull establishes a territory, he will scare off any challengers that threaten his authority over his home or his group. When a hippo yawns, it actually may be showing off enlarged canines to frighten a trespasser. These teeth can grow up to 50 cm (20 in.) long and are used if a confrontation becomes physical. Males ram each other with their mouths open, using their huge heads like sledgehammers and their big mouths as buckets to throw water at each other.

Hippo Tracks Ahead...
On land, hippos clear trails through vegetation which allow other animals easy access to water. They make these pathways while searching for their favorite food--short grasses. This keeps these grasses well trimmed, which stimulates new growth and discourages takeover by shrubs and trees.

Hippos spend most of their days in the water, where they defecate in substantial amounts. Their dung enriches the water with essential elements for a very important food chain that begins with a multitude of microorganisms. The microorganisms are eaten by fish which in turn are eaten by larger fish, aquatic reptiles, and birds. Native people also benefit when fishing, hunting, and traveling the trails and waterways.

Originally, hippopotami ranged throughout the continents of Asia, Europe, and Africa. Over the past several hundred years, even their remaining African range has decreased. They are still hunted for meat, for sport, and because they sometimes damage crops. People also use their large canines instead of elephant ivory. Today, these animals are found mainly in parks or on preserves where they are protected from poachers. In these safe havens, hippo numbers are slowly increasing.

Amphibious: adapted for both land and water