Hippopotamus
Overview
The hippopotamus or hippo, from the ancient Greek
Ancient Greek
Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...

 for "river horse" , is a large, mostly herbivorous
Herbivore
Herbivores are organisms that are anatomically and physiologically adapted to eat plant-based foods. Herbivory is a form of consumption in which an organism principally eats autotrophs such as plants, algae and photosynthesizing bacteria. More generally, organisms that feed on autotrophs in...

 mammal in sub-Saharan Africa
Sub-Saharan Africa
Sub-Saharan Africa as a geographical term refers to the area of the African continent which lies south of the Sahara. A political definition of Sub-Saharan Africa, instead, covers all African countries which are fully or partially located south of the Sahara...

, and one of only two extant species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 in the family Hippopotamidae
Hippopotamidae
Hippopotamuses are the members of the family Hippopotamidae. They are the only extant artiodactyls which walk on four toes on each foot.- Characteristics :...

 (the other is the Pygmy Hippopotamus
Pygmy Hippopotamus
The pygmy hippopotamus is a large mammal native to the forests and swamps of western Africa . The pygmy hippo is reclusive and nocturnal...

.) After the elephant
Elephant
Elephants are large land mammals in two extant genera of the family Elephantidae: Elephas and Loxodonta, with the third genus Mammuthus extinct...

 and rhinoceros
Rhinoceros
Rhinoceros , also known as rhino, is a group of five extant species of odd-toed ungulates in the family Rhinocerotidae. Two of these species are native to Africa and three to southern Asia....

, the hippopotamus is the third largest land mammal and the heaviest extant artiodactyl
Even-toed ungulate
The even-toed ungulates are ungulates whose weight is borne about equally by the third and fourth toes, rather than mostly or entirely by the third as in odd-toed ungulates such as horses....

.

The hippopotamus is semi-aquatic, inhabiting rivers, lakes and mangrove
Mangrove
Mangroves are various kinds of trees up to medium height and shrubs that grow in saline coastal sediment habitats in the tropics and subtropics – mainly between latitudes N and S...

 swamps where territorial bulls preside over a stretch of river and groups of 5 to 30 females and young.
Encyclopedia
The hippopotamus or hippo, from the ancient Greek
Ancient Greek
Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...

 for "river horse" , is a large, mostly herbivorous
Herbivore
Herbivores are organisms that are anatomically and physiologically adapted to eat plant-based foods. Herbivory is a form of consumption in which an organism principally eats autotrophs such as plants, algae and photosynthesizing bacteria. More generally, organisms that feed on autotrophs in...

 mammal in sub-Saharan Africa
Sub-Saharan Africa
Sub-Saharan Africa as a geographical term refers to the area of the African continent which lies south of the Sahara. A political definition of Sub-Saharan Africa, instead, covers all African countries which are fully or partially located south of the Sahara...

, and one of only two extant species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 in the family Hippopotamidae
Hippopotamidae
Hippopotamuses are the members of the family Hippopotamidae. They are the only extant artiodactyls which walk on four toes on each foot.- Characteristics :...

 (the other is the Pygmy Hippopotamus
Pygmy Hippopotamus
The pygmy hippopotamus is a large mammal native to the forests and swamps of western Africa . The pygmy hippo is reclusive and nocturnal...

.) After the elephant
Elephant
Elephants are large land mammals in two extant genera of the family Elephantidae: Elephas and Loxodonta, with the third genus Mammuthus extinct...

 and rhinoceros
Rhinoceros
Rhinoceros , also known as rhino, is a group of five extant species of odd-toed ungulates in the family Rhinocerotidae. Two of these species are native to Africa and three to southern Asia....

, the hippopotamus is the third largest land mammal and the heaviest extant artiodactyl
Even-toed ungulate
The even-toed ungulates are ungulates whose weight is borne about equally by the third and fourth toes, rather than mostly or entirely by the third as in odd-toed ungulates such as horses....

.

The hippopotamus is semi-aquatic, inhabiting rivers, lakes and mangrove
Mangrove
Mangroves are various kinds of trees up to medium height and shrubs that grow in saline coastal sediment habitats in the tropics and subtropics – mainly between latitudes N and S...

 swamps where territorial bulls preside over a stretch of river and groups of 5 to 30 females and young. During the day they remain cool by staying in the water or mud; reproduction and childbirth both occur in water. They emerge at dusk to graze on grass. While hippopotamuses rest near each other in the water, grazing is a solitary activity and hippos are not territorial on land.

Despite their physical resemblance to pig
Pig
A pig is any of the animals in the genus Sus, within the Suidae family of even-toed ungulates. Pigs include the domestic pig, its ancestor the wild boar, and several other wild relatives...

s and other terrestrial even-toed ungulates, their closest living relatives are cetacea
Cetacea
The order Cetacea includes the marine mammals commonly known as whales, dolphins, and porpoises. Cetus is Latin and is used in biological names to mean "whale"; its original meaning, "large sea animal", was more general. It comes from Ancient Greek , meaning "whale" or "any huge fish or sea...

ns (whale
Whale
Whale is the common name for various marine mammals of the order Cetacea. The term whale sometimes refers to all cetaceans, but more often it excludes dolphins and porpoises, which belong to suborder Odontoceti . This suborder also includes the sperm whale, killer whale, pilot whale, and beluga...

s, porpoise
Porpoise
Porpoises are small cetaceans of the family Phocoenidae; they are related to whales and dolphins. They are distinct from dolphins, although the word "porpoise" has been used to refer to any small dolphin, especially by sailors and fishermen...

s, etc.) from which they diverged about . The common ancestor of whales and hippos split from other even-toed ungulates around . The earliest known hippopotamus fossils, belonging to the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 Kenyapotamus
Kenyapotamus
Kenyapotamus is a possible ancestor of living hippopotamids that lived in Africa roughly 16 million to 8 million years ago during the Miocene epoch...

 in Africa, date to around .

The hippopotamus is recognizable by its barrel-shaped torso, enormous mouth and teeth, nearly hairless body, stubby legs and tremendous size. It is the third largest land mammal by weight (between 1½ and 3 tonnes), behind the white rhinoceros
White Rhinoceros
The White Rhinoceros or Square-lipped rhinoceros is one of the five species of rhinoceros that still exist. It has a wide mouth used for grazing and is the most social of all rhino species...

 (1½ to 3½ tonnes) and the three species of elephant
Elephant
Elephants are large land mammals in two extant genera of the family Elephantidae: Elephas and Loxodonta, with the third genus Mammuthus extinct...

 (3 to 9 tonnes). The hippopotamus is one of the largest quadrupeds (four legged mammals). Despite its stocky shape and short legs, it can easily outrun a human. Hippos have been clocked at 30 km/h (18.6 mph) over short distances. The hippopotamus is one of the most aggressive creatures in the world and is often regarded as one of the most dangerous animals in Africa. There are an estimated 125,000 to 150,000 hippos throughout Sub-Saharan Africa
Sub-Saharan Africa
Sub-Saharan Africa as a geographical term refers to the area of the African continent which lies south of the Sahara. A political definition of Sub-Saharan Africa, instead, covers all African countries which are fully or partially located south of the Sahara...

; Zambia
Zambia
Zambia , officially the Republic of Zambia, is a landlocked country in Southern Africa. The neighbouring countries are the Democratic Republic of the Congo to the north, Tanzania to the north-east, Malawi to the east, Mozambique, Zimbabwe, Botswana and Namibia to the south, and Angola to the west....

 (40,000) and Tanzania
Tanzania
The United Republic of Tanzania is a country in East Africa bordered by Kenya and Uganda to the north, Rwanda, Burundi, and the Democratic Republic of the Congo to the west, and Zambia, Malawi, and Mozambique to the south. The country's eastern borders lie on the Indian Ocean.Tanzania is a state...

 (20,000–30,000) possess the largest populations. They are still threatened by habitat loss and poaching for their meat and ivory
Ivory
Ivory is a term for dentine, which constitutes the bulk of the teeth and tusks of animals, when used as a material for art or manufacturing. Ivory has been important since ancient times for making a range of items, from ivory carvings to false teeth, fans, dominoes, joint tubes, piano keys and...

 canine teeth.

Etymology

The word "hippopotamus" is derived from the ancient Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...

 , hippopotamos, from , hippos, "horse", and , potamos, "river", meaning "horse of the river". In English, the plural
English plural
In the English language, nouns are inflected for grammatical number —that is, singular or plural. This article discusses the variety of ways in which English plurals are formed for nouns...

 is hippopotamuses, but hippopotami is also used; hippos can be used as a short plural. Hippopotamuses are gregarious, living in groups of up to 30 animals; such a group is called a pod, herd, dale, or bloat.

Classification

The hippopotamus is the type genus of the family Hippopotamidae
Hippopotamidae
Hippopotamuses are the members of the family Hippopotamidae. They are the only extant artiodactyls which walk on four toes on each foot.- Characteristics :...

. The Pygmy Hippopotamus
Pygmy Hippopotamus
The pygmy hippopotamus is a large mammal native to the forests and swamps of western Africa . The pygmy hippo is reclusive and nocturnal...

 belongs to a different genus in Hippopotamidae, either Choeropsis or Hexaprotodon
Hexaprotodon
Hexaprotodon is a genus of Hippopotamidae that is sometimes applied to the pygmy hippopotamus. Pygmy hippos may be classified as either Choeropsis liberiensis or Hexaprotodon liberiensis...

. Hippopotamidae are sometimes known as Hippopotamids. Sometimes the sub-family Hippopotaminae is used. Further, some taxonomists group hippopotamuses and anthracotheres in the super-family Anthracotheroidea or Hippopotamoidea.

Hippopotamidae are classified along with other even-toed ungulates in the order
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...

 Artiodactyla. Other artiodactyls include camels, cows, deer
Deer
Deer are the ruminant mammals forming the family Cervidae. Species in the Cervidae family include white-tailed deer, elk, moose, red deer, reindeer, fallow deer, roe deer and chital. Male deer of all species and female reindeer grow and shed new antlers each year...

 and pigs
PIGS
PIGS is a four letter acronym that can stand for:* PIGS , Phosphatidylinositol glycan anchor biosynthesis, class S, a human gene* PIGS , the economies of Portugal, Italy , Greece and Spain...

, although hippopotamuses are not closely related to these groups.

Five subspecies of hippos have been described based on morphological
Morphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....

 differences in their skulls and geographical differences:
  • H. a. amphibius – (the nominate subspecies) which stretched from Egypt
    Egypt
    Egypt , officially the Arab Republic of Egypt, Arabic: , is a country mainly in North Africa, with the Sinai Peninsula forming a land bridge in Southwest Asia. Egypt is thus a transcontinental country, and a major power in Africa, the Mediterranean Basin, the Middle East and the Muslim world...

    , where they are now extinct, south up the Nile River to Tanzania
    Tanzania
    The United Republic of Tanzania is a country in East Africa bordered by Kenya and Uganda to the north, Rwanda, Burundi, and the Democratic Republic of the Congo to the west, and Zambia, Malawi, and Mozambique to the south. The country's eastern borders lie on the Indian Ocean.Tanzania is a state...

     and Mozambique
    Mozambique
    Mozambique, officially the Republic of Mozambique , is a country in southeastern Africa bordered by the Indian Ocean to the east, Tanzania to the north, Malawi and Zambia to the northwest, Zimbabwe to the west and Swaziland and South Africa to the southwest...

    .
  • H. a. kiboko – in the Horn of Africa
    Horn of Africa
    The Horn of Africa is a peninsula in East Africa that juts hundreds of kilometers into the Arabian Sea and lies along the southern side of the Gulf of Aden. It is the easternmost projection of the African continent...

    , in Kenya
    Kenya
    Kenya , officially known as the Republic of Kenya, is a country in East Africa that lies on the equator, with the Indian Ocean to its south-east...

     and Somalia
    Somalia
    Somalia , officially the Somali Republic and formerly known as the Somali Democratic Republic under Socialist rule, is a country located in the Horn of Africa. Since the outbreak of the Somali Civil War in 1991 there has been no central government control over most of the country's territory...

    . Kiboko is the Swahili word for hippo. Broader nasals and more hollowed interorbital region.
  • H. a. capensis – from Zambia to South Africa
    South Africa
    The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...

    . Most flattened skull of the subspecies.
  • H. a. tschadensis – throughout Western Africa to, as the name suggests, Chad
    Chad
    Chad , officially known as the Republic of Chad, is a landlocked country in Central Africa. It is bordered by Libya to the north, Sudan to the east, the Central African Republic to the south, Cameroon and Nigeria to the southwest, and Niger to the west...

    . Slightly shorter and wider face, with prominent orbits.
  • H. a. constrictus – in Angola
    Angola
    Angola, officially the Republic of Angola , is a country in south-central Africa bordered by Namibia on the south, the Democratic Republic of the Congo on the north, and Zambia on the east; its west coast is on the Atlantic Ocean with Luanda as its capital city...

    , the southern Democratic Republic of Congo and Namibia
    Namibia
    Namibia, officially the Republic of Namibia , is a country in southern Africa whose western border is the Atlantic Ocean. It shares land borders with Angola and Zambia to the north, Botswana to the east and South Africa to the south and east. It gained independence from South Africa on 21 March...

    . Named for its deeper preorbital constriction.

The suggested subspecies were never widely used or validated by field biologists; the described morphological differences were small enough that they could have resulted from simple variation in non-representative samples. Genetic analyses have tested the existence of three of these putative subspecies. A study examining mitochondrial DNA
Mitochondrial DNA
Mitochondrial DNA is the DNA located in organelles called mitochondria, structures within eukaryotic cells that convert the chemical energy from food into a form that cells can use, adenosine triphosphate...

 from skin biopsies taken from 13 sampling locations, considered genetic diversity and structure among hippo populations across the continent. The authors found low but significant genetic differentiation among H. a. amphibius, H. a. capensis, and H. a. kiboko. Neither H.a.tschadensis nor H.a.constrictus have been tested.

Evolution

Until 1909, naturalists
Natural history
Natural history is the scientific research of plants or animals, leaning more towards observational rather than experimental methods of study, and encompasses more research published in magazines than in academic journals. Grouped among the natural sciences, natural history is the systematic study...

 grouped hippos with pig
Pig
A pig is any of the animals in the genus Sus, within the Suidae family of even-toed ungulates. Pigs include the domestic pig, its ancestor the wild boar, and several other wild relatives...

s, based on molar
Molar (tooth)
Molars are the rearmost and most complicated kind of tooth in most mammals. In many mammals they grind food; hence the Latin name mola, "millstone"....

 patterns. Several lines of evidence, first from blood
Blood
Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells....

 protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

s, then from molecular systematics and DNA
DNA
Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...


and the fossil record, show that their closest living relatives are cetaceans—whale
Whale
Whale is the common name for various marine mammals of the order Cetacea. The term whale sometimes refers to all cetaceans, but more often it excludes dolphins and porpoises, which belong to suborder Odontoceti . This suborder also includes the sperm whale, killer whale, pilot whale, and beluga...

s, dolphin
Dolphin
Dolphins are marine mammals that are closely related to whales and porpoises. There are almost forty species of dolphin in 17 genera. They vary in size from and , up to and . They are found worldwide, mostly in the shallower seas of the continental shelves, and are carnivores, mostly eating...

s and porpoise
Porpoise
Porpoises are small cetaceans of the family Phocoenidae; they are related to whales and dolphins. They are distinct from dolphins, although the word "porpoise" has been used to refer to any small dolphin, especially by sailors and fishermen...

s. The common ancestor of hippos and whales branched off from Ruminantia
Ruminantia
Ruminantia includes many of the well-known large grazing or browsing mammals: among them cattle, goats, sheep, deer, and antelope. All members of the Ruminantia are ruminants: they digest food in two steps, chewing and swallowing in the normal way to begin with, and then regurgitating the...

 and the rest of the even-toed ungulates; the cetacean and hippo lineages split soon afterwards.
The most recent theory of the origins of Hippopotamidae suggests that hippos and whales shared a common semi-aquatic ancestor that branched off from other artiodactyls around . This hypothesized ancestral group likely split into two branches around . One branch would evolve into cetaceans
Evolution of cetaceans
The cetaceans are marine mammal descendants of land mammals. Their terrestrial origins are indicated by:* Their need to breathe air from the surface;* The bones of their fins, which resemble the limbs of land mammals...

, possibly beginning about with the proto-whale Pakicetus
Pakicetus
Pakicetus is a genus of extinct terrestrial carnivorous mammal of the family Pakicetidae which was endemic to Pakistan from the Eocene .Pakicetus existed for approximately...

 and other early whale ancestors collectively known as Archaeoceti
Archaeoceti
Archaeocetes, or "ancient whales", are a paraphyletic group of cetaceans that gave rise to the modern cetaceans.The archaeocetes were once thought to have evolved from the mesonychids, based on dental characteristics...

, which eventually underwent aquatic adaptation
Aquatic adaptation
Several animal groups have undergone aquatic adaptation, going from being purely terrestrial animals to living at least part of the time in water. The adaptations in early speciation tend to develop as the animal ventures into water in order to find available food. As successive generations spend...

 into the completely aquatic cetacea
Cetacea
The order Cetacea includes the marine mammals commonly known as whales, dolphins, and porpoises. Cetus is Latin and is used in biological names to mean "whale"; its original meaning, "large sea animal", was more general. It comes from Ancient Greek , meaning "whale" or "any huge fish or sea...

ns.

The other branch became the anthracotheres
Anthracotheriidae
Anthracotheriidae is a family of extinct, hippopotamus-like artiodactyl ungulates related to hippopotamuses and whales. The oldest genus, Elomeryx, first appeared during the Middle Eocene in Asia...

, a large family of four-legged beasts, the earliest of whom in the late Eocene
Eocene
The Eocene Epoch, lasting from about 56 to 34 million years ago , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the...

 would have resembled skinny hippopotamuses with comparatively small and narrow heads. All branches of the anthracotheres, except that which evolved into Hippopotamidae
Hippopotamidae
Hippopotamuses are the members of the family Hippopotamidae. They are the only extant artiodactyls which walk on four toes on each foot.- Characteristics :...

, became extinct during the Pliocene
Pliocene
The Pliocene Epoch is the period in the geologic timescale that extends from 5.332 million to 2.588 million years before present. It is the second and youngest epoch of the Neogene Period in the Cenozoic Era. The Pliocene follows the Miocene Epoch and is followed by the Pleistocene Epoch...

 without leaving any descendants.

A rough evolutionary lineage can be traced from Eocene and Oligocene
Oligocene
The Oligocene is a geologic epoch of the Paleogene Period and extends from about 34 million to 23 million years before the present . As with other older geologic periods, the rock beds that define the period are well identified but the exact dates of the start and end of the period are slightly...

 species: Anthracotherium
Anthracotherium
Anthracotherium was a genus of extinct artiodactyl ungulate mammals, characterized by having 44 teeth, with five semi-crescentic cusps on the crowns of the upper molars. The genus ranged throughout the Oligocene period, having a distribution throughout Europe, Asia, and North America...

 and Elomeryx
Elomeryx
Elomeryx is an extinct genus of artiodactyl ungulate, and is among the earliest known anthracotheres. The genus was extremely widespread, first being found in Asia in the middle Eocene, in Europe during the latest Eocene, and having spread to North America by the early Oligocene.Elomeryx was about...

 to the Miocene
Miocene
The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...

  Merycopotamus
Merycopotamus
Merycopotamus is an extinct genus of Asian anthracothere that appeared during the Middle Miocene, and died out in the Late Pliocene. At the height of the genus' influence, species ranged throughout southern Asia. With the extinction of the last species, M. dissimilis, the lineage of...

 and Libycosaurus
Libycosaurus
Libycosaurus was one of the last anthracothere genera. It lived from the Middle to the Late Miocene, and ranged throughout Central and Northern Africa, and in Uganda, in what was then a lush, marshy environment....

 and the very latest anthracotheres in the Pliocene
Pliocene
The Pliocene Epoch is the period in the geologic timescale that extends from 5.332 million to 2.588 million years before present. It is the second and youngest epoch of the Neogene Period in the Cenozoic Era. The Pliocene follows the Miocene Epoch and is followed by the Pleistocene Epoch...

. Merycopotamus, Libycosaurus and all hippopotamids can be considered to form a clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...

, with Libycosaurus being more closely related to hippos. Their common ancestor would have lived in the Miocene, about .

Hippopotamids are therefore deeply nested within the family Anthracotheriidae. The Hippopotamidae are believed to have evolved in Africa; the oldest known hippopotamid is the genus Kenyapotamus
Kenyapotamus
Kenyapotamus is a possible ancestor of living hippopotamids that lived in Africa roughly 16 million to 8 million years ago during the Miocene epoch...

 which lived in Africa from 16 to . While hippopotamid species spread across Asia and Europe, no hippopotamuses have ever been discovered in the Americas, although various anthracothere genera emigrated into North America during the early Oligocene
Oligocene
The Oligocene is a geologic epoch of the Paleogene Period and extends from about 34 million to 23 million years before the present . As with other older geologic periods, the rock beds that define the period are well identified but the exact dates of the start and end of the period are slightly...

. From 7.5 to an ancestor to the modern hippopotamus, Archaeopotamus
Archaeopotamus
Archaeopotamus is an extinct genus of Hippopotamidae that lived between 7.5 and 1.8 million years ago in Africa and the Middle East. The genus was described in 2005 to encompass species of hippos that were previously grouped in Hexaprotodon....

, lived in Africa and the Middle East.

While the fossil record of hippos is still poorly understood, the two modern genera, Hippopotamus and Choeropsis (sometimes Hexaprotodon
Hexaprotodon
Hexaprotodon is a genus of Hippopotamidae that is sometimes applied to the pygmy hippopotamus. Pygmy hippos may be classified as either Choeropsis liberiensis or Hexaprotodon liberiensis...

), may have diverged as far back as . Taxonomists disagree whether or not the modern Pygmy Hippopotamus
Pygmy Hippopotamus
The pygmy hippopotamus is a large mammal native to the forests and swamps of western Africa . The pygmy hippo is reclusive and nocturnal...

 is a member of Hexaprotodon —an apparently paraphyletic genus also embracing many extinct Asian hippopotamuses that is more closely related to Hippopotamus, or Choeropsis —an older and basal
Basal (phylogenetics)
In phylogenetics, a basal clade is the earliest clade to branch in a larger clade; it appears at the base of a cladogram.A basal group forms an outgroup to the rest of the clade, such as in the following example:...

 genus.

Extinct species

Three species of Malagasy Hippopotamus
Malagasy Hippopotamus
Several species of Malagasy Hippopotamus lived on the island of Madagascar but are now believed to be extinct. The animals were very similar to the extant Hippopotamus and Pygmy Hippopotamus...

 became extinct during the Holocene
Holocene
The Holocene is a geological epoch which began at the end of the Pleistocene and continues to the present. The Holocene is part of the Quaternary period. Its name comes from the Greek words and , meaning "entirely recent"...

 on Madagascar
Madagascar
The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...

, one of them within the past 1,000 years. The Malagasy Hippos were smaller than the modern hippopotamus, likely through the process of insular dwarfism
Insular dwarfism
Insular dwarfism, a form of phyletic dwarfism, is the process and condition of the reduction in size of large animals – typically mammals – when their population's range is limited to a small environment, primarily islands. This natural process is distinct from the intentional creation of dwarf...

. There is fossil evidence that many Malagasy Hippos were hunted by humans, a likely factor in their eventual extinction. Isolated members of Malagasy Hippopotamus may have survived in remote pockets; in 1976, villagers described a living animal called the Kilopilopitsofy, which may have been a Malagasy Hippopotamus.

Two species of Hippopotamus, the European Hippopotamus
European Hippopotamus
Hippopotamus antiquus, sometimes called the European Hippopotamus, was a species of hippopotamus that ranged across Europe, becoming extinct some time before the last ice age at the end of the Pleistocene epoch. H. antiquus ranged from the Iberian Peninsula to the British Isles to the Rhine River...

 (H. antiquus) and H. gorgops
Hippopotamus gorgops
Hippopotamus gorgops is an extinct species of hippopotamus. It first appeared in Africa during the late Miocene, and eventually migrated into Europe during the early Pliocene . It became extinct prior to the Ice Age.With a length of and a shoulder height of H...

 ranged throughout continental Europe and the British Isles. Both species became extinct before the last glaciation. Ancestors of European Hippos found their way to many islands of the Mediterranean during the Pleistocene
Pleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....

. Both species were larger than the modern hippopotamus, averaging about 1 meter (3.3 feet) longer.

The Pleistocene also saw a number of dwarf species evolve on several Mediterranean islands including Crete
Crete
Crete is the largest and most populous of the Greek islands, the fifth largest island in the Mediterranean Sea, and one of the thirteen administrative regions of Greece. It forms a significant part of the economy and cultural heritage of Greece while retaining its own local cultural traits...

 (H. creutzburgi), Cyprus
Cyprus
Cyprus , officially the Republic of Cyprus , is a Eurasian island country, member of the European Union, in the Eastern Mediterranean, east of Greece, south of Turkey, west of Syria and north of Egypt. It is the third largest island in the Mediterranean Sea.The earliest known human activity on the...

 (H. minor
Cyprus Dwarf Hippopotamus
The Cyprus Dwarf Hippopotamus or Cypriot Pygmy Hippopotamus is an extinct species of hippopotamus that inhabited the island of Cyprus until the early Holocene....

), Malta
Malta
Malta , officially known as the Republic of Malta , is a Southern European country consisting of an archipelago situated in the centre of the Mediterranean, south of Sicily, east of Tunisia and north of Libya, with Gibraltar to the west and Alexandria to the east.Malta covers just over in...

 (H. melitensis
Maltese Hippopotamus
Hippopotamus melitensis is an extinct hippopotamus. It arrived after the Messinian salinity crisis and lived during the Pleistocene on Malta. The absence of predators led to the dwarfing of the hippos...

) and Sicily
Sicily
Sicily is a region of Italy, and is the largest island in the Mediterranean Sea. Along with the surrounding minor islands, it constitutes an autonomous region of Italy, the Regione Autonoma Siciliana Sicily has a rich and unique culture, especially with regard to the arts, music, literature,...

 (H. pentlandi
Sicilian Hippopotamus
Hippopotamus pentlandi is an extinct hippopotamus. It arrived after the Messinian salinity crisis and lived during the Pleistocene on Sicily...

). Of these, the Cyprus Dwarf Hippopotamus, survived until the end of the Pleistocene
Pleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....

 or early Holocene. Evidence from an archaeological site Aetokremnos
Aetokremnos
Aetokremnos is a rock shelter near Limassol on the southern coast of Cyprus. It is situated on a steep cliff site ca. 40m above the Mediterranean. The name means "Cliff of the eagles" in Greek.Ca. 40 m2 have been excavated. Of the four layers found, No...

, continues to cause debate on whether or not the species was encountered, and was driven to extinction, by man.

Description

Hippopotamuses are among the largest living mammals; only elephant
Elephant
Elephants are large land mammals in two extant genera of the family Elephantidae: Elephas and Loxodonta, with the third genus Mammuthus extinct...

s and some rhinoceros
Rhinoceros
Rhinoceros , also known as rhino, is a group of five extant species of odd-toed ungulates in the family Rhinocerotidae. Two of these species are native to Africa and three to southern Asia....

es and whale
Whale
Whale is the common name for various marine mammals of the order Cetacea. The term whale sometimes refers to all cetaceans, but more often it excludes dolphins and porpoises, which belong to suborder Odontoceti . This suborder also includes the sperm whale, killer whale, pilot whale, and beluga...

s are heavier. They can live in the water or on land. Their specific gravity
Specific gravity
Specific gravity is the ratio of the density of a substance to the density of a reference substance. Apparent specific gravity is the ratio of the weight of a volume of the substance to the weight of an equal volume of the reference substance. The reference substance is nearly always water for...

 allows them to sink and walk or run along the bottom of a river. Hippos are considered megafauna
Megafauna
In terrestrial zoology, megafauna are "giant", "very large" or "large" animals. The most common thresholds used are or...

, but unlike all other African megafauna, hippos have adapted
Adaptation
An adaptation in biology is a trait with a current functional role in the life history of an organism that is maintained and evolved by means of natural selection. An adaptation refers to both the current state of being adapted and to the dynamic evolutionary process that leads to the adaptation....

 for a semi-aquatic life in freshwater lakes and rivers.

Because of their enormous size, hippopotamuses are difficult to weigh in the wild. Most estimates of the weight come from culling
Culling
Culling is the process of removing animals from a group based on specific criteria. This is done either to reinforce certain desirable characteristics or to remove certain undesirable characteristics from the group...

 operations that were carried out in the 1960s. The average weights for adult males ranged between 1500 –. Females are smaller than their male counterparts, with average weights measuring between 1300 –. Older males can get much larger, reaching at least 3200 kg (7,054.8 lb) and occasionally weighing 4500 kg (9,920.8 lb). Male hippos appear to continue growing throughout their lives; females reach a maximum weight at around age 25.

On the National Geographic Channel
National Geographic Channel
National Geographic Channel, also commercially abbreviated and trademarked as Nat Geo, is a subscription television channel that airs non-fiction television programs produced by the National Geographic Society. Like History and the Discovery Channel, the channel features documentaries with factual...

 television program, "Dangerous Encounters with Brady Barr", Dr. Brady Barr
Brady Barr
Brady Barr is a herpetologist and currently the host of Nat Geo WILD's Dangerous Encounters with Brady Barr. He has been employed with National Geographic since 1997 ,HE learned field work and about snakes by the first herpitologist Samyak and Sourabh...

 measured the bite force
Force
In physics, a force is any influence that causes an object to undergo a change in speed, a change in direction, or a change in shape. In other words, a force is that which can cause an object with mass to change its velocity , i.e., to accelerate, or which can cause a flexible object to deform...

 of an adult female hippo at 8100 N (1821 lbf); Barr also attempted to measure the bite pressure of an adult male hippo, but had to abandon the attempt due to the male's aggressiveness. Hippopotamus teeth sharpen themselves as they grind together.

Hippos measure 3.3 to 5.2 m (10.8 to 17.1 ft) long, including a tail of about 56 centimetres (22 in) in length and average about 1.5 meters (5 ft) tall at the shoulder. The range of hippopotamus sizes overlaps with the range of the White Rhinoceros
White Rhinoceros
The White Rhinoceros or Square-lipped rhinoceros is one of the five species of rhinoceros that still exist. It has a wide mouth used for grazing and is the most social of all rhino species...

; use of different metrics makes it unclear which is the largest land animal after elephant
Elephant
Elephants are large land mammals in two extant genera of the family Elephantidae: Elephas and Loxodonta, with the third genus Mammuthus extinct...

s. Even though they are bulky animals, hippopotamuses can run faster than a human on land. Estimates of their running speed vary from 30 km/h (18 mph) to 40 km/h (25 mph), or even 50 km/h (30 mph). The hippo can maintain these higher speeds for only a few hundred meters.
A hippo's lifespan is typically 40 to 50 years. Donna the Hippo, 60, is the oldest living hippo in captivity. She lives at the Mesker Park Zoo
Mesker Park Zoo
The Mesker Park Zoo and Botanic Garden is a zoo that opened in 1928 in Evansville, Indiana. It is one of the oldest and largest zoos in the state...

 in Evansville, Indiana
Evansville, Indiana
Evansville is the third-largest city in the U.S. state of Indiana and the largest city in Southern Indiana. As of the 2010 census, the city had a total population of 117,429. It is the county seat of Vanderburgh County and the regional hub for both Southwestern Indiana and the...

, USA. The oldest hippo ever recorded was called Tanga; she lived in Munich, Germany, and died in 1995 at the age of 61.

The eyes, ears, and nostrils of hippos are placed high on the roof of the skull. This allows them to be in the water with most of their body submerged in the waters and mud of tropical
Tropics
The tropics is a region of the Earth surrounding the Equator. It is limited in latitude by the Tropic of Cancer in the northern hemisphere at approximately  N and the Tropic of Capricorn in the southern hemisphere at  S; these latitudes correspond to the axial tilt of the Earth...

 rivers to stay cool and prevent sunburn
Sunburn
A sunburn is a burn to living tissue, such as skin, which is produced by overexposure to ultraviolet radiation, commonly from the sun's rays. Usual mild symptoms in humans and other animals include red or reddish skin that is hot to the touch, general fatigue, and mild dizziness. An excess of UV...

. Their skeletal structure is graviportal, adapted to carrying the animals' enormous weight. Hippopotamuses have small legs (relative to other megafauna
Megafauna
In terrestrial zoology, megafauna are "giant", "very large" or "large" animals. The most common thresholds used are or...

) because the water in which they live reduces the weight burden. Unlike most other semi-aquatic animals, the hippopotamus has very little hair.

Their skin secretes a natural sunscreen
Sunscreen
Sunblock is a lotion, spray, gel or other topical product that absorbs or reflects some of the sun's ultraviolet radiation on the skin exposed to sunlight and thus helps protect against sunburn...

 substance which is red-colored. The secretion is sometimes referred to as "blood sweat," but is neither blood nor sweat. This secretion is initially colorless and turns red-orange within minutes, eventually becoming brown. Two distinct pigment
Pigment
A pigment is a material that changes the color of reflected or transmitted light as the result of wavelength-selective absorption. This physical process differs from fluorescence, phosphorescence, and other forms of luminescence, in which a material emits light.Many materials selectively absorb...

s have been identified in the secretions, one red (hipposudoric acid
Hipposudoric acid
Hipposudoric acid is a red pigment found in the skin secretions of the hippopotamus; although the secretions are often known as "blood sweat" , they are neither blood nor sweat....

) and one orange (norhipposudoric acid). The two pigments are highly acid
Acid
An acid is a substance which reacts with a base. Commonly, acids can be identified as tasting sour, reacting with metals such as calcium, and bases like sodium carbonate. Aqueous acids have a pH of less than 7, where an acid of lower pH is typically stronger, and turn blue litmus paper red...

ic compounds. Both pigments inhibit the growth of disease-causing bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...

; as well, the light absorption of both pigments peaks in the ultraviolet
Ultraviolet
Ultraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV...

 range, creating a sunscreen effect. All hippos, even those with different diets, secrete the pigments, so it does not appear that food is the source of the pigments. Instead, the animals may synthesize the pigments from precursors
Protein precursor
A protein precursor, also called a pro-protein or pro-peptide, is an inactive protein that can be turned into an active form by posttranslational modification. The name of the precursor for a protein is often prefixed by pro...

 such as the amino acid
Amino acid
Amino acids are molecules containing an amine group, a carboxylic acid group and a side-chain that varies between different amino acids. The key elements of an amino acid are carbon, hydrogen, oxygen, and nitrogen...

 tyrosine
Tyrosine
Tyrosine or 4-hydroxyphenylalanine, is one of the 22 amino acids that are used by cells to synthesize proteins. Its codons are UAC and UAU. It is a non-essential amino acid with a polar side group...

.

Distribution

Hippopotamus amphibius was widespread in North Africa
North Africa
North Africa or Northern Africa is the northernmost region of the African continent, linked by the Sahara to Sub-Saharan Africa. Geopolitically, the United Nations definition of Northern Africa includes eight countries or territories; Algeria, Egypt, Libya, Morocco, South Sudan, Sudan, Tunisia, and...

 and Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

 during the Eemian and late Pleistocene until about 30,000 years ago. The species was common in Egypt
Egypt
Egypt , officially the Arab Republic of Egypt, Arabic: , is a country mainly in North Africa, with the Sinai Peninsula forming a land bridge in Southwest Asia. Egypt is thus a transcontinental country, and a major power in Africa, the Mediterranean Basin, the Middle East and the Muslim world...

's Nile
Nile
The Nile is a major north-flowing river in North Africa, generally regarded as the longest river in the world. It is long. It runs through the ten countries of Sudan, South Sudan, Burundi, Rwanda, Democratic Republic of the Congo, Tanzania, Kenya, Ethiopia, Uganda and Egypt.The Nile has two major...

 region until historic times but has since been extirpated. Pliny the Elder
Pliny the Elder
Gaius Plinius Secundus , better known as Pliny the Elder, was a Roman author, naturalist, and natural philosopher, as well as naval and army commander of the early Roman Empire, and personal friend of the emperor Vespasian...

 writes that, in his time, the best location in Egypt for capturing this animal was in the Saite nome
Sais, Egypt
Sais or Sa el-Hagar was an ancient Egyptian town in the Western Nile Delta on the Canopic branch of the Nile. It was the provincial capital of Sap-Meh, the fifth nome of Lower Egypt and became the seat of power during the Twenty-fourth dynasty of Egypt and the Saite Twenty-sixth dynasty of Egypt ...

; the animal could still be found along the Damietta
Damietta
Damietta , also known as Damiata, or Domyat, is a port and the capital of the Damietta Governorate in Egypt. It is located at the intersection between the Mediterranean Sea and the Nile, about north of Cairo.-History:...

 branch after the Arab Conquest in 639. Hippos are still found in the rivers and lakes of Uganda
Uganda
Uganda , officially the Republic of Uganda, is a landlocked country in East Africa. Uganda is also known as the "Pearl of Africa". It is bordered on the east by Kenya, on the north by South Sudan, on the west by the Democratic Republic of the Congo, on the southwest by Rwanda, and on the south by...

, Sudan
Sudan
Sudan , officially the Republic of the Sudan , is a country in North Africa, sometimes considered part of the Middle East politically. It is bordered by Egypt to the north, the Red Sea to the northeast, Eritrea and Ethiopia to the east, South Sudan to the south, the Central African Republic to the...

, Somalia
Somalia
Somalia , officially the Somali Republic and formerly known as the Somali Democratic Republic under Socialist rule, is a country located in the Horn of Africa. Since the outbreak of the Somali Civil War in 1991 there has been no central government control over most of the country's territory...

, Kenya
Kenya
Kenya , officially known as the Republic of Kenya, is a country in East Africa that lies on the equator, with the Indian Ocean to its south-east...

, northern Democratic Republic of the Congo
Democratic Republic of the Congo
The Democratic Republic of the Congo is a state located in Central Africa. It is the second largest country in Africa by area and the eleventh largest in the world...

 and Ethiopia
Ethiopia
Ethiopia , officially known as the Federal Democratic Republic of Ethiopia, is a country located in the Horn of Africa. It is the second-most populous nation in Africa, with over 82 million inhabitants, and the tenth-largest by area, occupying 1,100,000 km2...

, west through Ghana
Ghana
Ghana , officially the Republic of Ghana, is a country located in West Africa. It is bordered by Côte d'Ivoire to the west, Burkina Faso to the north, Togo to the east, and the Gulf of Guinea to the south...

 to Gambia, and also in Southern Africa
Southern Africa
Southern Africa is the southernmost region of the African continent, variably defined by geography or geopolitics. Within the region are numerous territories, including the Republic of South Africa ; nowadays, the simpler term South Africa is generally reserved for the country in English.-UN...

 (Botswana
Botswana
Botswana, officially the Republic of Botswana , is a landlocked country located in Southern Africa. The citizens are referred to as "Batswana" . Formerly the British protectorate of Bechuanaland, Botswana adopted its new name after becoming independent within the Commonwealth on 30 September 1966...

, Republic of South Africa, Zimbabwe
Zimbabwe
Zimbabwe is a landlocked country located in the southern part of the African continent, between the Zambezi and Limpopo rivers. It is bordered by South Africa to the south, Botswana to the southwest, Zambia and a tip of Namibia to the northwest and Mozambique to the east. Zimbabwe has three...

, Zambia
Zambia
Zambia , officially the Republic of Zambia, is a landlocked country in Southern Africa. The neighbouring countries are the Democratic Republic of the Congo to the north, Tanzania to the north-east, Malawi to the east, Mozambique, Zimbabwe, Botswana and Namibia to the south, and Angola to the west....

). A separate population exists in Tanzania
Tanzania
The United Republic of Tanzania is a country in East Africa bordered by Kenya and Uganda to the north, Rwanda, Burundi, and the Democratic Republic of the Congo to the west, and Zambia, Malawi, and Mozambique to the south. The country's eastern borders lie on the Indian Ocean.Tanzania is a state...

 and Mozambique
Mozambique
Mozambique, officially the Republic of Mozambique , is a country in southeastern Africa bordered by the Indian Ocean to the east, Tanzania to the north, Malawi and Zambia to the northwest, Zimbabwe to the west and Swaziland and South Africa to the southwest...

. They like to dwell in places with permanent water that isn't too deep.

Conservation status

Genetic evidence suggests that common hippos in Africa experienced a marked population expansion during or after the Pleistocene Epoch, attributed to an increase in water bodies at the end of the era. These findings have important conservation implications as hippo populations across the continent are currently threatened by loss of access to fresh water. Hippos are also subject to unregulated hunting and poaching
Poaching
Poaching is the illegal taking of wild plants or animals contrary to local and international conservation and wildlife management laws. Violations of hunting laws and regulations are normally punishable by law and, collectively, such violations are known as poaching.It may be illegal and in...

. In May 2006 the hippopotamus was identified as a vulnerable species
Vulnerable species
On 30 January 2010, the IUCN Red List of Threatened Species identified 9694 Vulnerable species, subspecies and varieties, stocks and sub-populations.-References:...

 on the IUCN Red List
IUCN Red List
The IUCN Red List of Threatened Species , founded in 1963, is the world's most comprehensive inventory of the global conservation status of biological species. The International Union for Conservation of Nature is the world's main authority on the conservation status of species...

 drawn up by the World Conservation Union
World Conservation Union
The International Union for Conservation of Nature and Natural Resources is an international organization dedicated to finding "pragmatic solutions to our most pressing environment and development challenges." The organization publishes the IUCN Red List, compiling information from a network of...

 (IUCN), with an estimated population of between 125,000 and 150,000 hippos, a decline of between 7% and 20% since the IUCN's 1996 study.

The hippo population declined most dramatically in the Democratic Republic of the Congo
Democratic Republic of the Congo
The Democratic Republic of the Congo is a state located in Central Africa. It is the second largest country in Africa by area and the eleventh largest in the world...

. The population in Virunga National Park
Virunga National Park
The Virunga National Park , formerly named Albert National Park, is a 7800 square km National Park that stretches from the Virunga Mountains in the South, to the Rwenzori Mountains in the North, in the eastern Democratic Republic of Congo, bordering Volcanoes National Park in Rwanda and Rwenzori...

 had dropped to 800 or 900 from around 29,000 in the mid 1970s. The decline is attributed to the disruptions caused by the Second Congo War
Second Congo War
The Second Congo War, also known as Coltan War and the Great War of Africa, began in August 1998 in the Democratic Republic of the Congo , and officially ended in July 2003 when the Transitional Government of the Democratic Republic of the Congo took power; however, hostilities continue to this...

. The poachers are believed to be former Hutu
Hutu
The Hutu , or Abahutu, are a Central African people, living mainly in Rwanda, Burundi, and eastern DR Congo.-Population statistics:The Hutu are the largest of the three peoples in Burundi and Rwanda; according to the United States Central Intelligence Agency, 84% of Rwandans and 85% of Burundians...

 rebels, poorly paid Congolese soldiers, and local militia groups. Reasons for poaching include the belief that hippos are harmful to society, and also for money. The sale of hippo meat is illegal, but black-market sales are difficult for Virunga National Park
Virunga National Park
The Virunga National Park , formerly named Albert National Park, is a 7800 square km National Park that stretches from the Virunga Mountains in the South, to the Rwenzori Mountains in the North, in the eastern Democratic Republic of Congo, bordering Volcanoes National Park in Rwanda and Rwenzori...

 officers to track.

Invasive potential

In the late 1980s, Pablo Escobar
Pablo Escobar
Pablo Emilio Escobar Gaviria was a Colombian drug lord. He was an elusive cocaine trafficker and rich and successful criminal. He owned numerous luxury residences, automobiles, and even airplanes...

 kept four hippos in a private menagerie at his residence in Hacienda Napoles
Hacienda Napoles
Hacienda Nápoles is the luxurious estate built and owned by Colombian drug lord Pablo Escobar in Puerto Triunfo, Antioquia...

, 100 km east of Medellín
Medellín
Medellín , officially the Municipio de Medellín or Municipality of Medellín, is the second largest city in Colombia. It is in the Aburrá Valley, one of the more northerly of the Andes in South America. It has a population of 2.3 million...

, Colombia
Colombia
Colombia, officially the Republic of Colombia , is a unitary constitutional republic comprising thirty-two departments. The country is located in northwestern South America, bordered to the east by Venezuela and Brazil; to the south by Ecuador and Peru; to the north by the Caribbean Sea; to the...

, after buying them in New Orleans. They were deemed too difficult to seize and move after Escobar's fall, and hence left on the untended estate. By 2007, the animals had multiplied to 16 and had taken to roaming the area for food in the nearby Magdalena River
Magdalena River
The Magdalena River is the principal river of Colombia, flowing northward about through the western half of the country. It takes its name from the biblical figure Mary Magdalene. It is navigable through much of its lower reaches, in spite of the shifting sand bars at the mouth of its delta, as...

. In 2009, two adults and one calf escaped the herd, and after attacking humans and killing cattle, one of the adults (called "Pepe") was killed by hunters under authorization of the local authorities. It is unknown what kind of effects the presence of hippos might have on the ecosystem in Colombia. According to experts interviewed by W Radio
W Radio
W Radio is the branding of several radio stations, including:*W Radio México*W Radio Los Angeles*W Radio *Caracol Miami...

 Colombia, the animals could survive in the Colombian jungles. It is believed that the lack of control from the Colombian government, which is not used to dealing with this species, could result in human fatalities.

Behavior

Hippos spend most of their days wallowing in the water or the mud, with the other members of their pod. The water serves to keep their body temperature down, and to keep their skin from drying out. With the exception of eating, most of hippopotamuses' lives —from childbirth, fighting with other hippos, to reproduction— occur in the water.

Hippos leave the water at dusk and travel inland, sometimes up to 8 kilometers (5 mi), to graze on short grass, their main source of food. They spend four to five hours grazing and can consume 68 kilograms (150 lb) of grass each night. Like almost any herbivore, they will consume many other plants if presented with them, but their diet in nature consists almost entirely of grass, with only minimal consumption of aquatic plants. Hippos have (rarely) been filmed eating carrion
Carrion
Carrion refers to the carcass of a dead animal. Carrion is an important food source for large carnivores and omnivores in most ecosystems. Examples of carrion-eaters include vultures, hawks, eagles, hyenas, Virginia Opossum, Tasmanian Devils, coyotes, Komodo dragons, and burying beetles...

, usually close to the water. There are other reports of meat-eating, and even cannibalism
Cannibalism
Cannibalism is the act or practice of humans eating the flesh of other human beings. It is also called anthropophagy...

 and predation
Predation
In ecology, predation describes a biological interaction where a predator feeds on its prey . Predators may or may not kill their prey prior to feeding on them, but the act of predation always results in the death of its prey and the eventual absorption of the prey's tissue through consumption...

. The stomach anatomy of a hippo is not suited to carnivory, and meat-eating is likely caused by aberrant behavior or nutritional stress.

The diet of hippos consists mostly of terrestrial grasses, even though they spend most of their time in the water. Most of their defecation occurs in the water, creating allochthonous deposits of organic matter along the river beds. These deposits have an unclear ecological function. Because of their size and their habit of taking the same paths to feed, hippos can have a significant impact on the land they walk across, both by keeping the land clear of vegetation and depressing the ground. Over prolonged periods hippos can divert the paths of swamps and channels.

Adult hippos move at speeds up to 8 km/h (5 mph) in water. Adult hippos typically resurface to breathe every three to five minutes. The young have to breathe every two to three minutes. The process of surfacing and breathing is automatic, and even a hippo sleeping underwater will rise and breathe without waking. A hippo closes its nostrils when it submerges.

As with fish and turtles on a coral reef, hippo occasionally visit cleaning stations and signal by wide-open mouth their readiness for being cleaned of parasites by certain species of fish. This situation is an example of mutualism
Mutualism
Mutualism is the way two organisms of different species biologically interact in a relationship in which each individual derives a fitness benefit . Similar interactions within a species are known as co-operation...

 in which the hippo benefits from the cleansing while the fish receive food.

Social life

Studying the interaction of male and female hippopotamuses has long been complicated by the fact that hippos are not sexually dimorphic and thus females and young males are almost indistinguishable in the field. Although hippos like to lie close to each other, they do not seem to form social bonds except between mothers and daughters, and are not social animals. The reason they huddle close together is unknown.

Hippopotamuses are territorial only in water, where a bull presides over a small stretch of river, on average 250 meters in length, and containing ten females. The largest pods can contain up to 100 hippos. Other bachelors are allowed in a bull's stretch, as long as they behave submissively toward the bull. The territories of hippos exist to establish mating rights. Within the pods, the hippos tend to segregate by gender. Bachelors will lounge near other bachelors, females with other females, and the bull on his own. When hippos emerge from the water to graze, they do so individually.

Hippopotamuses appear to communicate verbally, through grunts and bellows, and it is thought that they may practice echolocation
Animal echolocation
Echolocation, also called biosonar, is the biological sonar used by several kinds of animals.Echolocating animals emit calls out to the environment and listen to the echoes of those calls that return from various objects near them. They use these echoes to locate and identify the objects...

, but the purpose of these vocalizations is currently unknown. Hippos have the unique ability to hold their head partially above the water and send out a cry that travels through both water and air; hippos above and under water will respond.

Reproduction

Female hippos reach sexual maturity at five to six years of age and have a gestation period
Pregnancy (mammals)
In mammals, pregnancy is the period of reproduction during which a female carries one or more live offspring from implantation in the uterus through gestation. It begins when a fertilized zygote implants in the female's uterus; and ends once it leaves the uterus.-Fertilization and implantation:A...

 of 8 months. A study of endocrine system
Endocrine system
In physiology, the endocrine system is a system of glands, each of which secretes a type of hormone directly into the bloodstream to regulate the body. The endocrine system is in contrast to the exocrine system, which secretes its chemicals using ducts. It derives from the Greek words "endo"...

s revealed that female hippopotamuses may begin puberty as early as 3 or 4 years of age. Males reach maturity at around 7.5 years.

A study of hippopotamus reproductive behavior in Uganda showed that peak conceptions occurred during the end of the wet season in the summer, and peak births occurred toward the beginning of the wet season in late winter. This is because of the female's estrous cycle
Estrous cycle
The estrous cycle comprises the recurring physiologic changes that are induced by reproductive hormones in most mammalian placental females. Estrous cycles start after puberty in sexually mature females and are interrupted by anestrous phases or pregnancies...

; as with most large mammals, male hippopotamus spermatozoa is active year round. Studies of hippos in Zambia and South Africa also showed evidence of births occurring at the start of the wet season. After becoming pregnant, a female hippopotamus will typically not begin ovulation again for 17 months.

Mating occurs in the water with the female submerged for most of the encounter, her head emerging periodically to draw breath. Hippos are one of the few mammals that give birth under water, along with Cetaceans and Sirenia
Sirenia
Sirenia is an order of fully aquatic, herbivorous mammals that inhabit swamps, rivers, estuaries, marine wetlands, and coastal marine waters. Four species are living, in two families and genera. These are the dugong and manatees...

ns (manatee
Manatee
Manatees are large, fully aquatic, mostly herbivorous marine mammals sometimes known as sea cows...

s and dugong
Dugong
The dugong is a large marine mammal which, together with the manatees, is one of four living species of the order Sirenia. It is the only living representative of the once-diverse family Dugongidae; its closest modern relative, Steller's sea cow , was hunted to extinction in the 18th century...

s). Baby hippos are born underwater at a weight between 25 and 45 kg (60–110 lb) and an average length of around 127 cm (50 in) and must swim to the surface to take their first breath. A mother typically gives birth to only one hippo, although twins also occur. The young often rest on their mothers' backs when in water that is too deep for them, and they swim underwater to suckle. They also will suckle on land when the mother leaves the water. Weaning
Weaning
Weaning is the process of gradually introducing a mammal infant, either human or animal, to what will be its adult diet and withdrawing the supply of its mother's milk.The process takes place only in mammals, as only mammals produce milk...

 starts between six and eight months after birth and most calves are fully weaned after a year.

Like many other large mammals, hippos are described as K-strategists, in this case typically producing just one large, well-developed infant every couple of years (rather than large numbers of small, poorly developed young several times per year as is common among small mammals such as rodents).

Aggression

Hippopotamuses are by nature very aggressive animals, especially when young calves are present. Frequent targets of their aggression include crocodile
Crocodile
A crocodile is any species belonging to the family Crocodylidae . The term can also be used more loosely to include all extant members of the order Crocodilia: i.e...

s, which often inhabit the same river habitat as hippos. Nile crocodile
Nile crocodile
The Nile crocodile or Common crocodile is an African crocodile which is common in Somalia, Ethiopia, Uganda, Kenya, Egypt, Tanzania, Zambia, Zimbabwe, Gabon, South Africa, Malawi, Sudan, Botswana, and Cameroon...

s, lion
Lion
The lion is one of the four big cats in the genus Panthera, and a member of the family Felidae. With some males exceeding 250 kg in weight, it is the second-largest living cat after the tiger...

s, and spotted hyena
Spotted Hyena
The spotted hyena also known as laughing hyena, is a carnivorous mammal of the family Hyaenidae, of which it is the largest extant member. Though the species' prehistoric range included Eurasia extending from Atlantic Europe to China, it now only occurs in all of Africa south of the Sahara save...

s are known to prey on young hippos. Hippos are very aggressive towards humans, whom they commonly attack whether in boats or on land with no apparent provocation. They are widely considered to be one of the most dangerous large animals in Africa.

To mark territory, hippos spin their tails while defecating to distribute their excrement over a greater area. Likely for the same reason, hippos are retromingent-- that is, they urinate backwards.

Hippos rarely kill each other, even in territorial challenges. Usually a territorial bull and a challenging bachelor will stop fighting when it is clear that one hippo is stronger. When hippos become overpopulated, or when a habitat starts to shrink, bulls will sometimes attempt to kill infants, but this behavior is not common under normal conditions. Some incidents of hippo cannibalism have been documented, but it is believed to be the behavior of distressed or sick hippos, and not healthy behavior.

Hippos and humans

The earliest evidence of human interaction with hippos comes from butchery cut marks upon hippo bones at Bouri Formation
Bouri Formation
The Bouri Formation is an area in the Middle Awash Valley, in Ethiopia that has provided a rich source of Australopithecines and Homo fossils, artifacts and bones of large mammal with cut marks from butchery...

 dated around 160,000 years ago. Later rock paintings and engravings showing hippos being hunted have been found in the mountains of the central Sahara
Sahara
The Sahara is the world's second largest desert, after Antarctica. At over , it covers most of Northern Africa, making it almost as large as Europe or the United States. The Sahara stretches from the Red Sea, including parts of the Mediterranean coasts, to the outskirts of the Atlantic Ocean...

 dated 4,000–5,000 years ago near Djanet
Djanet
Djanet is an oasis city in southeast Algeria. It is located in Illizi Province, 412 kilometers from Illizi. It is inhabited by the Kel Ajjer Tuareg people. It is the capital of Djanet District.-Transport:...

 in the Tassili n'Ajjer Mountains
Tassili n'Ajjer
Tassili n'Ajjer is a mountain range in the Algerian section of the Sahara Desert. It is a vast plateau in south-east Algeria at the borders of Libya, Niger and Mali, covering an area of 72,000 sq...

. Hippos were also well-known to the ancient Egyptians, where the hippo was recognized as a ferocious denizen of the Nile
Nile
The Nile is a major north-flowing river in North Africa, generally regarded as the longest river in the world. It is long. It runs through the ten countries of Sudan, South Sudan, Burundi, Rwanda, Democratic Republic of the Congo, Tanzania, Kenya, Ethiopia, Uganda and Egypt.The Nile has two major...

. In Ancient Egyptian Religion, the hippopotamus-headed Tawaret
Tawaret
In Egyptian mythology, Taweret is the Egyptian Goddess of childbirth and fertility. The name "Taweret" means, "she who is great" or simply, "great one"...

 was a goddess of protection in pregnancy and childbirth, because ancient Egyptians recognized the protective nature of a female hippopotamus toward her young.

The hippopotamus has been known to historians since classical antiquity
Classical antiquity
Classical antiquity is a broad term for a long period of cultural history centered on the Mediterranean Sea, comprising the interlocking civilizations of ancient Greece and ancient Rome, collectively known as the Greco-Roman world...

. The Greek historian Herodotus
Herodotus
Herodotus was an ancient Greek historian who was born in Halicarnassus, Caria and lived in the 5th century BC . He has been called the "Father of History", and was the first historian known to collect his materials systematically, test their accuracy to a certain extent and arrange them in a...

 described the hippopotamus in The Histories
Histories (Herodotus)
The Histories of Herodotus is considered one of the seminal works of history in Western literature. Written from the 450s to the 420s BC in the Ionic dialect of classical Greek, The Histories serves as a record of the ancient traditions, politics, geography, and clashes of various cultures that...

 (written circa
Circa
Circa , usually abbreviated c. or ca. , means "approximately" in the English language, usually referring to a date...

 440 BC) and the Roman Historian Pliny the Elder
Pliny the Elder
Gaius Plinius Secundus , better known as Pliny the Elder, was a Roman author, naturalist, and natural philosopher, as well as naval and army commander of the early Roman Empire, and personal friend of the emperor Vespasian...

 wrote about the hippopotamus in his encyclopedia Naturalis Historia
Naturalis Historia
The Natural History is an encyclopedia published circa AD 77–79 by Pliny the Elder. It is one of the largest single works to have survived from the Roman Empire to the modern day and purports to cover the entire field of ancient knowledge, based on the best authorities available to Pliny...

 (written circa 77 AD).

Zulu warriors preferred to be as brave as a hippopotamus, since even lions were not considered as brave. "In 1888, Captain Baden-Powell
Robert Baden-Powell, 1st Baron Baden-Powell
Robert Stephenson Smyth Baden-Powell, 1st Baron Baden-Powell, Bt, OM, GCMG, GCVO, KCB , also known as B-P or Lord Baden-Powell, was a lieutenant-general in the British Army, writer, and founder of the Scout Movement....

 was part of a column searching for the Zulu chief Dinizulu, who was leading the Usutu people in revolt against the British colonists. The column was joined by John Dunn, a white Zulu chief, who led an impi
Impi
An Impi is an isiZulu word for any armed body of men. However, in English it is often used to refer to a Zulu regiment, which is called an ibutho in Zulu. Its beginnings lie far back in historic tribal warfare customs, where groups of armed men called impis battled...

 (army) of 2000 Zulu warriors to join the British."

The words of the Zulu anthem sounded like this:

"Een-gonyama Gonyama!
"Invooboo! Yah-bo! Yah-bo! Invooboo!"

"John Dunn was at the head of his impi. [Baden Powell] asked him to translate the Zulu anthem his men had been singing. Dunn laughed and replied: "He is a lion. Yes, he is better than a lion—he is a hippopotamus."

Hippos in zoos

Hippopotamuses have long been popular zoo animals. The first zoo hippo in modern history was Obaysch
Obaysch
Obaysch was the first hippopotamus seen in England since prehistoric times, and the first in Europe since Ancient Rome. He was captured on an island on the White Nile when he was less than one year old...

 who arrived at the London Zoo
London Zoo
London Zoo is the world's oldest scientific zoo. It was opened in London on 27 April 1828, and was originally intended to be used as a collection for scientific study. It was eventually opened to the public in 1847...

 on May 25, 1850, where he attracted up to 10,000 visitors a day and inspired a popular song, the Hippopotamus Polka. Hippos have remained popular zoo animals since Obaysch, and generally breed well in captivity. Their birth rates are lower than in the wild, but this is attributed to zoos' not wanting to breed as many hippos as possible, since hippos are large and relatively expensive animals to maintain.

Most hippos in zoos were born in captivity. There are enough hippos in the international zoo system that introducing further animals from the wild will be unnecessary if zoos cooperate to maintain the genetic diversity of the breeding stock.

Like many zoo animals, hippos were traditionally displayed in concrete exhibits. In the case of hippos, they usually had a pool of water and patch of grass. In the 1980s, zoo designers increasingly designed exhibits that reflected the animals' native habitats. The best known of these, the Toledo Zoo Hippoquarium, features a 360,000 gallon pool for hippos. In 1987, researchers were able to tape, for the first time, an underwater birth (as in the wild) at the Toledo Zoo. The exhibit was so popular that the hippos became the logo of the Toledo Zoo
Toledo Zoo
Toledo Zoo is a zoo located in Toledo, Ohio. The zoo began in 1900 as Toledo Zoological Gardens and operated by the City of Toledo's Parks Board. In 1982 ownership was transferred from the city to Toledo Zoological Society, a private non-profit organization, and professionalized the zoo's management...

.

Cultural depictions

The Hippopotamus was known to the Greeks and Romans as the Beast of the Nile
Nile
The Nile is a major north-flowing river in North Africa, generally regarded as the longest river in the world. It is long. It runs through the ten countries of Sudan, South Sudan, Burundi, Rwanda, Democratic Republic of the Congo, Tanzania, Kenya, Ethiopia, Uganda and Egypt.The Nile has two major...

. A red hippo also represented the Ancient Egyptian god Set
Set (mythology)
Set was in Ancient Egyptian religion, a god of the desert, storms, and foreigners. In later myths he was also the god of darkness, and chaos...

; the thigh is the 'phallic leg of set' symbolic of virility. Set's consort Tawaret
Tawaret
In Egyptian mythology, Taweret is the Egyptian Goddess of childbirth and fertility. The name "Taweret" means, "she who is great" or simply, "great one"...

 was also seen as part hippo. The Behemoth
Behemoth
Behemoth is a mythological beast mentioned in the Book of Job, 40:15-24. Metaphorically, the name has come to be used for any extremely large or powerful entity.-Plural as singular:...

 from the Book of Job
Book of Job
The Book of Job , commonly referred to simply as Job, is one of the books of the Hebrew Bible. It relates the story of Job, his trials at the hands of Satan, his discussions with friends on the origins and nature of his suffering, his challenge to God, and finally a response from God. The book is a...

, 40:15–24 is also thought to be based on a hippo.

Ever since Obaysch
Obaysch
Obaysch was the first hippopotamus seen in England since prehistoric times, and the first in Europe since Ancient Rome. He was captured on an island on the White Nile when he was less than one year old...

 inspired the Hippopotamus Polka, hippos have been popular animals in Western culture
Western culture
Western culture, sometimes equated with Western civilization or European civilization, refers to cultures of European origin and is used very broadly to refer to a heritage of social norms, ethical values, traditional customs, religious beliefs, political systems, and specific artifacts and...

 for their rotund appearance that many consider comical. Stories of hippos like Huberta who became a celebrity in South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...

 in the 1930s for trekking across the country; or the tale of Owen and Mzee
Owen and Mzee
Owen and Mzee are a hippopotamus and an Aldabra giant tortoise, respectively, that became the subject of media attention after forming an unusual bond of friendship. They live in Haller Park, Malindi, Kenya....

, a hippo and tortoise who developed an intimate bond; have amused people who have bought hippo books, merchandise, and many a stuffed hippo toy. Hippos were mentioned in the novelty Christmas song "I Want a Hippopotamus for Christmas
I Want a Hippopotamus for Christmas
I Want a Hippopotamus for Christmas is a Christmas novelty song written by John Rox and performed by Gayla Peevey in 1953. The song peaked at number 24 on Billboard magazine's pop chart in December 1953.-History:...

" that became a hit for child star Gayla Peevey
Gayla Peevey
Gayla Peevey is a former singer and child star from Ponca City, Oklahoma. She is best known for her recording of "I Want a Hippopotamus for Christmas" . Peevey recorded the novelty song when she was 10 years old....

 in 1953. They also feature in the songs "The Hippopotamus" and "Hippo Encore" by Flanders and Swann
Flanders and Swann
The British duo Flanders and Swann were the actor and singer Michael Flanders and the composer, pianist and linguist Donald Swann , who collaborated in writing and performing comic songs....

, with the famous refrain Mud, Mud, Glorious Mud. They even inspired a popular board game, Hungry Hungry Hippos
Hungry Hungry Hippos
Hungry Hungry Hippos is a tabletop game made for young children, currently produced by Hasbro, under the brand of its subsidiary, Milton Bradley. It was published in 1967 and introduced in 1978...

.

Hippos have also been popular cartoon characters, where their rotund frame is used for humorous effect. The Disney
The Walt Disney Company
The Walt Disney Company is the largest media conglomerate in the world in terms of revenue. Founded on October 16, 1923, by Walt and Roy Disney as the Disney Brothers Cartoon Studio, Walt Disney Productions established itself as a leader in the American animation industry before diversifying into...

 film Fantasia
Fantasia (film)
Fantasia is a 1940 American animated film produced by Walt Disney and released by Walt Disney Productions. The third feature in the Walt Disney Animated Classics series, the film consists of eight animated segments set to pieces of classical music conducted by Leopold Stokowski, seven of which are...

 featured a ballerina hippopotamus dancing to the opera, La Gioconda
La Gioconda (opera)
La Gioconda is an opera in four acts by Amilcare Ponchielli set to an Italian libretto by Arrigo Boito, based on Angelo, tyran de Padoue, a play in prose by Victor Hugo, dating from 1835...

. Other cartoon hippos have included Hanna-Barbera
Hanna-Barbera
Hanna-Barbera Productions, Inc. was an American animation studio that dominated North American television animation during the second half of the 20th century...

's Peter Potamus
Peter Potamus
Peter Potamus is an animated television series produced by Hanna-Barbera and first broadcast on September 16, 1964. -Premise:Peter Potamus was a syndicated series divided into three segments; one of Peter Potamus and So-So, one of...

, the book and TV series George and Martha
George and Martha
George and Martha is an animated children's television show which comprises 26 episodes made in 1999. The program revolves around the lives of two hippos: George and Martha...

, Flavio and Marita on the Animaniacs
Animaniacs
Steven Spielberg Presents Animaniacs, usually referred to as simply Animaniacs, is an American animated series, distributed by Warner Bros. Television and produced by Amblin Entertainment and Warner Bros. Animation. The cartoon was the second animated series produced by the collaboration of Steven...

, Pat of the French duo Pat et Stanley
Pat et Stanley
Pat et Stanley is a French animated show that appears as part of the children's television programme TFou on the French network TF1. Animated by Pierre Coffin, Pat the hippopotamus and Stan the dog have appeared in 362 short episodes as well as the 26 minute movie Pat et Stanley: Le Trésor de Pit...

, The Backyardigan's
The Backyardigans
The Backyardigans is a Canadian/American 3-D CGI-animated children's TV series, created by Janice Burgess. It features five animal children, who imagine that their backyard becomes an adventure place. It is a coproduction of Treehouse TV, and the Canadian animation studio Nelvana. Debuting on...

 Tasha, and Gloria and Moto-Moto from the Madagascar
Madagascar (film series)
Madagascar is an animated film series produced by DreamWorks Animation. Voices of Ben Stiller, Jada Pinkett Smith, Chris Rock and David Schwimmer are featured in the films...

 franchise. A Sesame Street
Sesame Street
Sesame Street has undergone significant changes in its history. According to writer Michael Davis, by the mid-1970s the show had become "an American institution". The cast and crew expanded during this time, including the hiring of women in the crew and additional minorities in the cast. The...

 cartoon from the early 1970s features a hippo who lives in the country and likes it quiet, while being disturbed when the mouse
Mouse
A mouse is a small mammal belonging to the order of rodents. The best known mouse species is the common house mouse . It is also a popular pet. In some places, certain kinds of field mice are also common. This rodent is eaten by large birds such as hawks and eagles...

 who likes it loud moves in with her.

The hippopotamus characters "Happy Hippos" were created in 1988 by the French designer Andre Roche based in Munich, to be hidden in the "Kinder Surprise
Kinder Surprise
Kinder Surprise, also known as a Kinder Egg or, in the original Italian, Kinder Sorpresa, is a confection manufactured by Italian company Ferrero. Originally intended for children, it has the form of a chocolate egg containing a small toy, often requiring assembly.-Overview:Kinder Surprise...

 egg" of the Italian chocolate company Ferrero SpA
Ferrero SpA
Ferrero SpA is an Italian manufacturer of chocolate and other confectionery products, founded by confectioner Pietro Ferrero in 1946 and based in Alba, Piedmont, Italy. The company achieved success headed by Pietro's son Michele Ferrero, then Michele's son Pietro , who oversaw global business...

. These characters were not placid like real hippos but rather cute and lively, and had such a success that they reappeared several times in different products of this company in the following years, increasing their popularity worldwide each time. The Nintendo Company published in the years 2001 and 2007 Game Boy adventures of them.

In the game of chess
Chess
Chess is a two-player board game played on a chessboard, a square-checkered board with 64 squares arranged in an eight-by-eight grid. It is one of the world's most popular games, played by millions of people worldwide at home, in clubs, online, by correspondence, and in tournaments.Each player...

, the hippopotamus lends its name to the Hippopotamus Defense, an opening system, which is generally considered weak.

Hippopotamus was one of the many exotic animals brought to fight gladiators in Rome by the emperor Philip I the Arab
Philip the Arab
Philip the Arab , also known as Philip or Philippus Arabs, was Roman Emperor from 244 to 249. He came from Syria, and rose to become a major figure in the Roman Empire. He achieved power after the death of Gordian III, quickly negotiating peace with the Sassanid Empire...

 to commemorate Rome's 1000 years anniversary in 248 AD. Silver coins with hippo's image were minted that year.

The River Horse
River Horse (sculpture)
The River Horse is a bronze sculpture on the campus of George Washington University. It is located at Lisner Auditorium, at 21st Street and H Street, Northwest, Washington, D.C., in the Foggy Bottom neighborhood....

 is a popular outdoor sculpture at George Washington University
George Washington University
The George Washington University is a private, coeducational comprehensive university located in Washington, D.C. in the United States...

, Washington, D.C.
Washington, D.C.
Washington, D.C., formally the District of Columbia and commonly referred to as Washington, "the District", or simply D.C., is the capital of the United States. On July 16, 1790, the United States Congress approved the creation of a permanent national capital as permitted by the U.S. Constitution....



External links

  • IUCN Hippo Specialist Group
  • Hippos of Lake Edward a blog about the last significant group of Hippos in Virunga National Park
    Virunga National Park
    The Virunga National Park , formerly named Albert National Park, is a 7800 square km National Park that stretches from the Virunga Mountains in the South, to the Rwenzori Mountains in the North, in the eastern Democratic Republic of Congo, bordering Volcanoes National Park in Rwanda and Rwenzori...

    , DRC
    Democratic Republic of the Congo
    The Democratic Republic of the Congo is a state located in Central Africa. It is the second largest country in Africa by area and the eleventh largest in the world...

  • Pablo Escobar's Fugitive Hippo Shot Dead by The Telegraph
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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