At first glance, hippos seem to be gentle and slow animals. Apart from elephants, which are the only ones larger than them, they are the largest animals in Africa. They are also very strong and fast, which combined with their size makes them one of the most dangerous African animals. Although they spend most of their time in the water and their closest relatives are whales, they are poor swimmers but good runners on land. Unfortunately, these animals are becoming increasingly scarce and the species has been classified as vulnerable to extinction.
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The hippopotamus (Hippopotamus) is a cloven-hoofed mammal from the hippopotamus family (Hippopotamidae).
Hippos are characterized by a massive body structure, thick folded skin, almost devoid of hair, and a thick layer of subcutaneous fatty tissue. They lead an amphibious lifestyle and can remain underwater for a long time. Hippos, along with other families, are classified in the order Artiodactyla, which includes, among others: camels, cattle, deer and pigs. Despite this, hippos are not closely related to these animals.
There are two species in the hippopotamus family today: the Nile hippopotamus and the pygmy hippopotamus (a much smaller species found in the rainforests and swamps of West Africa).
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The ancient Greeks believed that the hippopotamus was related to the horse (hippo meaning horse).
Until 1985, naturalists grouped hippos with domestic pigs based on the structure of their teeth. Data obtained from the study of blood proteins, molecular phylogeny (pathways of ancestral development, origin and evolutionary changes), DNA and fossils indicate that their closest living relatives are cetaceans - whales, porpoises, dolphins, etc. General The ancestor of whales and hippos diverged from other artiodactyls about 60 million years ago.
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The genus Hippopotamus includes one living species found in Africa.
This is the Nile hippopotamus (Hippopotamus amphibius), whose name comes from ancient Greek and means “river horse” (ἱπποπόταμος).
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Hippos are one of the largest living mammals.
Due to its size, such an individual is difficult to weigh in the wild. Estimates suggest that the average weight of adult males is 1500-1800 kg. Females are smaller than males, their average weight is 1300-1500 kg. Older males can even weigh more than 3000 kg. Hippos reach their maximum body weight late in their lives. Females reach their maximum body weight at about 25 years of age.
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Hippos reach an average of 3,5-5 meters in length and 1,5 meters in height at the withers.
The head can weigh up to 225 kg. These animals can open their mouths to a width of about 1 meter, and the length of their teeth reaches a maximum of 30 cm.
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Hippos lead an amphibious lifestyle.
Most often they stay in the water during the day and are active only at dusk and at night. Then they go ashore and chew grass in the meadows near the water (they also feed on aquatic plants). In search of food, they can go up to 8 km inland.
On land, despite their gigantic size, they can run faster than humans. Their speed can range from 30 to 40, and sometimes 50 km/h, but only over short distances, up to several hundred meters.
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They have a characteristic appearance.
Their body is barrel-shaped and hairless. Bristles are present only on the muzzle and tail. The legs are short, the head is large. Their skeleton is adapted to withstand the large weight of the animal; the water in which they live reduces their weight due to the buoyancy of the body. The eyes, ears and nostrils are located high on the roof of the skull, thanks to which these animals can be almost completely submerged in the water and silt of tropical rivers. Animals cool down under water, which protects them from sunburn.
Hippos are also characterized by long tusks (about 30 cm) and four toes connected by a webbed membrane.
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Their skin, approximately 4 centimeters thick, makes up 25% of their body weight.
It is protected from the sun by a substance it secretes, which is a natural solar filter. This discharge, which is neither blood nor sweat, is initially colorless, after a few minutes it turns red-orange and finally brown. It is composed of two pigments (red and orange) that are strong acidic chemical compounds, with the red pigment additionally having bacteriostatic properties and likely being an antibiotic. The light absorption of both pigments has a maximum in the ultraviolet range, which protects hippos from excessive heat. Because of the color of their secretions, hippos are said to “sweat blood.”
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Hippos live about 40 years in the wild and up to 50 in captivity.
The oldest known hippopotamus living in captivity at the Evansville Zoo in Indiana was the hippopotamus "Donna", who lived there for 56 years. One of the oldest hippos in the world, 55-year-old Hipolis, died in 2016 at the Chorzow Zoo. He lived with one partner, Khamba, for 45 years. Together they had 14 descendants. Khamba died in 2011.
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Besides eating, hippos spend their entire lives in water.
They spend up to 16 hours a day there as a way to cool off. They live primarily in freshwater habitats, but populations in West Africa primarily inhabit estuaries and can even be found at sea. They are not the most experienced swimmers - they swim at a speed of 8 km/h. Adults cannot swim in water, but only stand in shallow water. Juveniles can float on the surface of the water and often swim, moving their hind limbs. They come to the surface to breathe every 4-6 minutes. Juveniles are able to close their nostrils when submerged in water. The process of ascent and breathing occurs automatically, and even a hippopotamus sleeping under water emerges without waking up.
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Hippos breed in water and are born in water.
Females reach sexual maturity at 5-6 years, and males at 7,5 years. A couple copulates in the water. Pregnancy lasts 8 months. Hippos are one of the few mammals born underwater. Cubs are born with a weight of 25 to 45 kg and an average length of about 127 cm. Usually only one calf is born, although twin pregnancies do occur. Feeding of young animals with mother's milk also occurs in water, and weaning occurs after a year.
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They obtain food mainly on land.
They spend four to five hours a day eating and can eat up to 68 kg of food at a time. They feed mainly on grasses, to a lesser extent on aquatic plants, and in the absence of preferred food, on other plants. There are also known cases of scavenger behavior, carnivorous behavior, predation and even cannibalism, although the stomachs of hippopotamuses are not adapted to digest meat food. This is an unnatural behavior, possibly caused by a lack of proper nutrition.
The authors of the journal Mammal Review argue that predation is natural for the hippopotamus. In their opinion, this group of animals is characterized by a meat diet, since their closest relatives, whales, are carnivores.
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Hippos are only territorial in water.
Studying the relationships of hippopotamuses is difficult because they lack sexual dimorphism - males and females are practically indistinguishable. Although they remain close to each other, they do not form social bonds. In the water, the dominant males defend a certain section of the river, about 250 meters long, along with about 10 females. The largest such community numbers about 100 individuals. These territories are determined by the laws of copulation. There is gender segregation in the herd - they are grouped by sex. When feeding, they do not show territorial instinct.
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Hippos are very noisy.
The sounds they make are reminiscent of pig squeals, although they can also growl loudly. Their voice can be heard during the day, because at night they practically do not speak.
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Nile hippos live in a kind of symbiosis with some birds.
They allow golden herons to sit on their backs and eat the parasites and insects that torment them from their skin.
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Hippos are perceived as very aggressive animals.
They show aggression towards crocodiles that live in the same bodies of water, especially when young hippos are nearby.
There are also attacks on people, although there are no reliable statistics on this matter. It is estimated that around 500 people are killed each year in clashes between humans and hippos, but this information is passed down mainly by word of mouth from village to village, without verifying how the person actually died.
Hippos rarely kill each other. When a fight occurs between males, the fight is completed by the one who admits that the enemy is stronger.
It also happens that the males try to kill the offspring, or the female tries to kill the male, protecting the young - this happens only in emergency situations, when there is too little food and the area occupied by the herd is reduced.
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To mark their territory in the water, hippos behave rather strangely.
During defecation, they vigorously shake their tail to spread excrement as far as possible and urinate backwards.
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Hippos have been known to historians since ancient times.
The first images of these animals were rock paintings (carvings) in the mountains of central Sahara. One of them shows the moment of people hunting a hippopotamus.
In Egypt, these animals were considered dangerous to humans until they noticed how caringly female hippos treat their offspring. Since then, the goddess Toeris, the protector of pregnancy and the postpartum period, has been depicted as a woman with the head of a hippopotamus.
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There are fewer and fewer of these animals in the world.
In 2006, hippos were classified as vulnerable to extinction on the Red List of Threatened Species created by the International Union for Conservation of Nature (IUCN), with their population estimated at approximately 125 individuals. faces.
The main threat to hippos is cutting them off from freshwater bodies.
People also kill these animals for their meat, fat, skin and upper fangs.
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Currently, Nile hippos live only in central and southern Africa.
Most often they can be found in oases, lakes and rivers of Sudan, Somalia, Kenya and Uganda, as well as Ghana, Gambia, Botswana, South Africa, Zambia and Zimbabwe.
During the last ice age, hippos also lived in North Africa and even in Europe, since they are adapted to life in cold climates, as long as they had ice-free reservoirs at their disposal. However, they were exterminated by man.
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Thanks to drug lord Pablo Escobar, hippos were also found in Colombia.
The animals were brought to Escobar's private zoo at the Hacienda Napoles ranch in the 80s. The herd initially consisted of three females and one male. After Escobar's death in 1993, the exotic animals from this private zoo were moved to another location, but the hippos remained. It was difficult to find transport for these huge animals, and since then they lived their lives without bothering anyone.
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“Cocaine hippos” (they are called so because of the implications of their owner’s profession) have already spread 100 km from their original place of residence.
Nowadays, there are more and more of them in the Magdalena River basin, and residents of Medellin and the surrounding area have already become accustomed to their proximity - they have become a local tourist attraction.
Authorities do not consider the presence of hippos a problem at the moment, but in the future, when their population increases to 400-500 animals, they could pose a threat to the survival of other animals feeding in the same areas.
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Scientists estimate that there are currently about 80 hippos living in the region.
Since 2012, their population has almost doubled.
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The uncontrolled presence of these giant animals can significantly disrupt the local ecosystem.
According to research, hippopotamus excrement (defecation into water) changes the oxygen level in water bodies, which can negatively affect not only the organisms living there, but also people.
The animals also destroy crops and can be aggressive - a 45-year-old man was seriously injured after being attacked by a 'cocaine hippo'.
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The possibility of destroying Escobar's hippos was considered, but public opinion opposed it.
Enrique Cerda Ordonez, a biologist at the National University of Colombia, believes that castrating these animals would be the right solution to the problem, although due to their size it would be extremely difficult.
