- Average life span in the wild:
- Up to 40 years
- Head and body, 9.5 to 14 ft (2.8 to 4.2 m); tail, 13.75 to 19.75 inches (35 to 50 cm)
- 5,000 to 8,000 lbs (2,268 to 3,629 kg)
- Group name:
- Size relative to a 6-ft (2-m) man
Please add a "relative" entry to your dictionary.
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 five 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.
Hippos also bask on the shoreline and secrete an oily red substance, which gave rise to the myth that they sweat blood. 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.
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, and hyenas.
Hippos once had a broader distribution but now live in eastern central and southern sub-Saharan Africa, where their populations are in decline.
The loss of animal species is irreversible and potentially catastrophic, not to mention heartrendingly sad. Where do we stand? Face the facts with this quiz.
The Hawaiian monk seal is one of the oldest species of seal on the planet. But their tenure in paradise is perilously close to its end; only about 1,100 seals remain in the wild.
They’re rarely seen. Even less often photographed. Bryde’s whales rocket through Pacific shallows to gorge on fish. Dive in for more.
Find out what National Geographic Society is doing to save animals all over the world, and learn what you can do to help.