Sub-Saharan Africa is the home to the second heaviest land mammal in the world — the hippopotamus. Their dense bodies make it impossible for them to swim, even though they spend most of their time in the water. The body of the hippopotamus is well suited for aquatic life. Their eyes, ears and nostrils are located at the top of their head, so they are able to see, hear, and breathe while mostly submerged. A clear membrane covers and protects their eyes while allowing them to see underwater. Their nostrils close to keep water out, and they can hold their breath for several minutes.
As you can see from the pictures, Hippopotamuses love water, which is why the Greeks named them the “river horse.” Hippos spend up to 16 hours a day submerged in rivers and lakes to keep their massive bodies cool under the hot African sun. Hippos are graceful in water, good swimmers, and can hold their breath underwater for up to ten minutes. However, they are often large enough to simply walk or stand on the lake floor, or lie in the shallows. Their eyes and nostrils are located high on their heads, which allows them to see and breathe while mostly submerged.
Staying underwater helps the hippopotamus not feel the weight of its hulking frame. They can weigh up to 3600 kg (8000 lb.)! Under the water, hippos tap their feet along the ground to propel themselves. Being submerged for the most part of the day also helps keep the hippo cool and protected from the sun. When they do venture out of the water for a significant amount of time, hippos secrete a red-colored substance to cool their hairless skin. The secretion is referred to as ‘blood-sweat’ but is actually neither of those fluids. The liquid is actually a skin moistener and sunblock that may also provide protection against germs.
At sunset, hippopotamuses leave the water and travel overland to graze. They may travel 6 miles (10 kilometers) in a night, along single-file pathways, to consume some 80 pounds (35 kilograms) of grass. Considering their enormous size, a hippo’s food intake is relatively low. If threatened on land hippos may run for the water—they can match a human’s speed for short distances.
Though they feed on land, hippos do many other activities in the water, including mating and birthing. Groups of 10-30 hippos live together with one dominant male. During the dry season, the dominant male chooses a partner, and then the other males fight each other for the remaining females.
Eight months after conception, at the height of the wet season, female hippos give birth to one calf at a time, either on land or underwater. Afterwards, mothers leave the herd for a short period of time to bond with their calves underwater. After a few weeks, the calves finally exit the water to feed on grass.
Hippo calves weigh nearly 100 pounds (45 kilograms) at birth and can suckle on land or underwater by closing their ears and nostrils. Each female has only one calf every two years. Soon after birth, mother and young join schools that provide some protection against crocodiles, lions, hyenas and human beings.
Hippos once had a broader distribution but now live in eastern central and southern sub-Saharan Africa, where their populations are in decline.
While many people view the hippopotamus as a harmless and comic character, this is not actually the truth. In reality, the hippopotamus is a dangerous creature. They have powerful jaws and sharp teeth that can crush a crocodile or split a boat in two.
Despite being a vegetarian, the hippo is responsible for more human fatalities in Africa than any other animal, making it Africa’s most dangerous beast.
As you can see from the pictures, Hippos spend most of their day lolling about in water and as stated above, can stay submerged for more than 10 minutes. If a small fishing boat or canoe filled with tourists happens to be above their heads when they come up for air, there’s little to protect the vessel from capsizing. Anyone who has spent time in Southern African waters surrounded by pods of hippos can attest to the terrifying feeling you get when you’re surrounded by these huge snorting fellows. (The only land animal that’s bigger than the hippo is the elephant).
Male hippos actively defend their territories which run along the banks of the rivers and lakes where they live. Humans tend to get killed by hippos when they stand on a riverbank or beach that a male hippo considers to be his territory.
Females have also been known to get extremely aggressive if they sense anyone coming in between their babies, who stay in the water while she feeds on the shore. Hippos can run at speeds of over 20 miles an hour and they have enormous jaws which host up to 20 inch canines. There’s not a lot you can do if one comes straight at you.
Some more interesting facts about the hippo:
Hippos secrete a natural sunscreen that is colored red and eventually turns brown
The hippo’s closest living relative is the whale
Fully grown hippos consume over 100 pounds of vegetation per day.
Hippos regularly kill crocodiles
The hippo is in danger of becoming extinct
Hippos can’t jump
Hippos are listed by IUCN’s Red List as vulnerable due to loss of habitat. Hippopotamus habitats are infringed upon by humans, who use their grazing land for farming and also divert water for farming needs. War in the regions that hippos inhabit has also wrecked havoc on hippopotamus populations. Finally, poachers kill hippos for their ivory tusks and for for sport.
What You Can Do to Help
If you’d like to help hippos, avoid buying products made from their ivory tusks. Encourage others to boycott these products as well.
Hippopotamus Distribution map world wide.
Sub-Saharan Africa is the home to the second heaviest land mammal in the world, the hippopotamus.