The common hippopotamus (Hippopotamus amphibius), or hippo is a large semi-aquatic mammal that is found wallowing in the rivers and lakes across sub-Saharan Africa.
The name comes from the ancient Greek for “river horse” (ἱπποπόταμος).
But hippos are not related to horses at all—in fact, their closest living relatives may be pigs or whales and dolphins!
There are two species of hippopotamus: the common hippo and the much smaller pygmy hippo.
Hippos are the third largest living land mammals, after elephants and white rhinos.
They are 3.3 to 5 meters (10.8 to 16.5 feet) long and up to 1.6 meters (5.2 feet) tall at shoulders.
Females average weight is 1,400 kilograms (3,000 pounds); males weight from 1,600 to 4,500 kilograms (3,500 to 9,920 pounds).
A hippo’s lifespan is typically 40–50 years both captivity and the wild.The longest living hippopotamus exceeded 61 years in captivity.
Hippos are a semi-aquatic mammal, usually inhabiting shallow lakes, rivers, and swamps in Africa.
With their eyes, ears, and nostrils on the top of the head, hippos can hear, see, and breathe while most of their body is underwater.
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 5 minutes or longer.
Hippos can even sleep underwater, using a reflex that allows them to bob up, take a breath, and sink back down without waking up.
They spend up to 16 hours a day submerged in rivers and lakes to keep their massive bodies cool under the hot African sun.
Yet despite all these adaptations for life in the water, hippos can’t swim!
They move around by pushing off from the bottom of the river or simply walking along the riverbed in a slow-motion gallop, lightly touching the bottom with their toes, which are slightly webbed.
Hippos have unique skin that needs to be kept wet for a good part of the day.
Hippos lack scent and sweat glands. Instead, mucous glands secrete a thick oily layer of red pigmented fluid. For years this fluid was thought to be a mixture of blood and sweat, giving it the nickname “blood sweat.”
Like almost any herbivore, they consume other plants if presented with them, but their diet in nature consists almost entirely of grass, with only minimal consumption of aquatic plants.
At sunset, hippopotamuses leave the water and travel overland to graze. They may travel 10 kilometers (6 miles) in a night, along single-file pathways, to consume some 35 kilograms (80 pounds) of grass.
Hippos can store two days’ worth of grass in their stomachs and can go up to three weeks without eating.
Despite its stocky shape and short legs, it is capable of running 30 km/h (19 mph) over short distances.
The hippos is one of the most aggressive creatures in the world and is often regarded as one of the most dangerous animals in Africa.
Their canine and incisor teeth grow continuously, with canines reaching 51 centimeters (20 inches) in length. Hippo males especially use their canines for fighting.
Hippos are a very social species, living in groups of about 10 to 100. No matter the size, usually the group is led by a dominant male.
Dominant male has the right to mate with all adult females in his herd, although he sometimes allows subordinate males in and around his territory to mate.
Although breeding can occur year round, it is most common between February and August.
Females have a gestation period of eight months and have only one baby at a time.
When the female nears the time to give birth, she leaves the herd for one or two weeks to give birth to her young and create a bond with her baby. She is comfortable giving birth in water or on land.If the baby is born underwater, the mother needs to push it to the surface to breathe.
The mother stays in the water with her newborn for several days without eating, and she waits until her baby is strong enough before they dare leave the water at night to graze.
For 18 months, the baby nurses while its mother is on land, or it swims underwater to suckle.
At 5 to 7 years old, the hippo calf is fully mature.
Female usually mate every other year, due cost of parental investment into the young.
Occasionally lions, hyenas, and crocodiles will prey on young hippo.The adult hippo’s only real enemy (other than man) is his pool mate.They bite, maim, and kill each other.The bulls fight over females in breeding season and quarrel over water space at all times, especially in dry season.
The IUCN classified the Hippo as having vulnerable status in 2008. The population is in decline; declining most dramatically in the Democratic Republic of the Congo.
Hippos are endangered mainly because poachers hunt them for their meat and the ivory in their teeth. Other threats are habitat loss due to the encroachment of human settlements and the diversion of river water for agriculture.
Hippos are one of the noisiest animals in Africa: some hippo vocalizations have been measured at 115 decibels, about the same volume as being 5 meters (16 feet) away from the speakers at a rock concert!
Hippos vocalize on both land and in the water and are the only mammals that make amphibious calls.
In African rivers, hippos look like floating islands, with birds fishing from their backs.
Turtles and even baby crocodiles have been seen sunning themselves on hippos.
Several fish species in Africa can keep busy feeding on the food remnants and dead skin cells found on the hippo’s skin.
Hippos have stiff whiskers above the upper lip and some fuzziness around their ears and on their tail.
A group of hippos is sometimes called a bloat, pod, or siege.