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Rhinoceros
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Rhinoceros , often colloquially abbreviated rhino, is a name used to group five extant species of odd-toed ungulates in the family Rhinocerotidae. Two of these species are native to Africa and three to southern Asia. Three of the five species—the Javan, Sumatran and Black Rhinoceros—are critically endangered. The Indian is endangered, with fewer than 2700 individuals remaining in the wild. The White is registered as Vulnerable, with over 9,000 remaining in the wild.
The rhinoceros family is characterised by large size (one of the largest remaining megafauna alive today) with all of the species able to reach one ton or more in weight; herbivorous diet; and a thick protective skin, 1.5–5 cm thick, formed from layers of collagen positioned in a lattice structure; relatively small brains for mammals this size (400–600g); and a large horn.
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Rhinoceros , often colloquially abbreviated rhino, is a name used to group five extant species of odd-toed ungulates in the family Rhinocerotidae. Two of these species are native to Africa and three to southern Asia. Three of the five species—the Javan, Sumatran and Black Rhinoceros—are critically endangered. The Indian is endangered, with fewer than 2700 individuals remaining in the wild. The White is registered as Vulnerable, with over 9,000 remaining in the wild.
The rhinoceros family is characterised by large size (one of the largest remaining megafauna alive today) with all of the species able to reach one ton or more in weight; herbivorous diet; and a thick protective skin, 1.5–5 cm thick, formed from layers of collagen positioned in a lattice structure; relatively small brains for mammals this size (400–600g); and a large horn. They generally eat leafy material, although their ability to ferment food in their hindgut allows them to subsist on more fibrous plant matter, if necessary. Unlike other perissodactyls, the African species of rhinoceros lack teeth at the front of their mouths, relying instead on their powerful premolar and molar teeth to grind up plant food.
The rhino is prized for its horn. The horns of a rhinoceros are made of keratin, the same type of protein that makes up hair and fingernails. Both African species and the Sumatran Rhinoceros have two horns, while the Indian and Javan Rhinoceros have a single horn. Rhinoceri have acute hearing and sense of smell, but poor eyesight. Most live to be about 60 years old or more.
Taxonomy and naming
The word "rhinoceros" (?????e???) is derived from the Greek words ????? rhinos, meaning nose, and ???a? keras, meaning horn; hence "horned-nose". The plural can be rhinoceros, rhinoceri, rhinoceroses, or rhinoceroi. The collective noun for a group of rhinoceros is "crash". They are commonly known as rhinos.
The five living species fall into three categories. The two African species, the White Rhinoceros and the Black Rhinoceros, diverged during the early Pliocene (about 5 million years ago) but the Dicerotini group to which they belong originated in the middle Miocene, about 14.2 million years ago. The main difference between black and white rhinos is the shape of their mouths. White rhinos have broad flat lips for grazing and black rhinos have long pointed lips for eating foliage. A popular, if unverified theory, claims that the name White Rhinoceros was actually a mistake, or rather a corruption of the word wijd ("wide" in Afrikaans), referring to their square lips.
White Rhinoceros are divided into Northern and Southern subspecies. There are two living Rhinocerotini species, the endangered Indian Rhinoceros and the critically endangered Javan Rhinoceros, which diverged from one another about 10 million years ago. The critically endangered Sumatran Rhinoceros is the only surviving representative of the most primitive group, the Dicerorhinini, which emerged in the Miocene (about 20 million years ago). The extinct Woolly Rhinoceros of northern Europe and Asia was also a member of this tribe.
A subspecific hybrid white rhino (Ceratotherium s. simum Χ C. s. cottoni) was bred at the Dvur Krαlovι Zoo (Zoological Garden Dvur Kralove nad Labem) in the Czech Republic in 1977. Interspecific hybridisation of Black and White Rhinoceros has also been confirmed.
All rhinoceros species have 82 chromosomes (diploid number, 2N, per cell), except the Black Rhinoceros, which has 84. This is the highest known chromosome number of all mammals.
White Rhinoceros
The White Rhinoceros or Square-lipped Rhinoceros (Ceratotherium simum) is, after the elephant, the most massive remaining land animal in the world, along with the Indian Rhinoceros and the hippopotamus, which are of comparable size. There are two subspecies of White Rhinos; as of 2005, South Africa has the most of the first subspecies, the Southern White Rhinoceros (Ceratotherium simum simum). The population of Southern White Rhinos is about 14,500, making them the most abundant subspecies of rhino in the world. However, the population of the second subspecies, the critically-endangered Northern White Rhinoceros (Ceratotherium simum cottoni), is down to as few as four individuals in the wild, and as of June 2008 this sub-species could even be extinct.
The White Rhino has an immense body and large head, a short neck and broad chest. This rhino can exceed 3000 kg (6600 pounds), have a head-and-body length of 3.35-4.2 m (11-13.9 feet) and a shoulder height of 150-185 cm (60-73 inches). The record-sized White Rhinoceros was about 4500 kg (10,000 lb).. On its snout it has two horns. The front horn is larger than the other horn and averages 89.9 cm (23.6 inches) in length and can reach 150 cm (59 inches). The White Rhinoceros also has a noticeable hump on the back of its neck which supports its large head. The colour of this animal ranges from yellowish brown to slate grey. The only hair on them is on the ear fringes and tail bristles with little across the body. White Rhinos have the distinctive flat broad mouth which is used for grazing.
Black Rhinoceros
The name Black Rhinoceros (Diceros bicornis) was chosen to distinguish this species from the White Rhinoceros (Ceratotherium simum). This can be confusing, as those two species are not really distinguishable by colour. There are four subspecies of black rhino: South-central (Diceros bicornis minor), the most numerous, which once ranged from central Tanzania south through Zambia, Zimbabwe and Mozambique to northern and eastern South Africa; South-western (Diceros bicornis bicornis) which are better adapted to the arid and semi-arid savannas of Namibia, southern Angola, western Botswana and western South Africa; East African (Diceros bicornis michaeli), primarily in Tanzania; and West African (Diceros bicornis longipes) which was tentatively declared extinct in 2006. Only 8 of this subspecies are left in existence, all in captivity.
An adult Black Rhinoceros stands 147160 cm (57.963 inches) high at the shoulder and is 3.3-3.6 m (10.811.8 feet) in length. An adult weighs from 800 to 1400 kg (1,760 to 3,080 lb), exceptionally to 1820 kg (4,000 lb), with the females being smaller than the males. Two horns on the skull are made of keratin with the larger front horn typically 50 cm long, exceptionally up to 140 cm. Sometimes, a third smaller horn may develop. The Black Rhino is much smaller than the White Rhino, and has a pointed mouth, which they use to grasp leaves and twigs when feeding.
Indian Rhinoceros
The Indian Rhinoceros or the Great One-horned Rhinoceros (Rhinoceros unicornis) is found in Nepal and in Assam, India. The rhino once inhabited many areas of Pakistan to Burma and may have even roamed in China. But because of human influence their range has shrunk and now they only exist in small populations in north-eastern India , Nepal and in a national park in Pakistan.. It is confined to the tall grasslands and forests in the foothills of the Himalayas.
The Indian Rhinoceros has thick, silver-brown skin which creates huge folds all over its body. Its upper legs and shoulders are covered in wart-like bumps, and it has very little body hair. Fully-grown males are larger than females in the wild, weighing from 22003000 kg (4,8006,600 lb). Female Indian rhinos weigh about 1600 kg. The Indian Rhino is from 5.76.7 feet tall and can be up to long. The record-sized specimen of this rhino was approximately 3500 kg. The Indian Rhino has a single horn that reaches a length of between 20 and 101 cm. Its size is comparable to that of the White Rhino in Africa.
Two-thirds of the world's Great One-horned Rhinoceroses are now confined to the Kaziranga National Park situated in the Golaghat district of Assam, India.
Javan Rhinoceros
The Javan Rhinoceros (Rhinoceros sondaicus) is one of the rarest and most endangered large mammals anywhere in the world. According to 2002 estimates, only about 60 remain, in Java (Indonesia) and Vietnam. Of all the rhino species, the least is known of the Javan Rhino. These animals prefer dense lowland rain forest, tall grass and reed beds that are plentiful with large floodplains and mud wallows. Though once widespread throughout Asia, by the 1930s the rhinoceros was nearly hunted to extinction in India, Burma, Peninsular Malaysia, and Sumatra for the supposed medical powers of its horn and blood.
Like the closely related larger Indian Rhinoceros, the Javan rhinoceros has only a single horn. Its hairless, hazy gray skin fall into folds into the shoulder, back, and rump giving it an armored-like appearance. The Javan rhino's body length reaches up to 3.1-3.2 m (10-10.5 feet), including its head and a height of 1.51.7 m (4.9-5.6ft)tall. Adults are variously reported to weigh between 9001,400 kg or 1,360-2,000 kg. Males horns can reach 26 cm in length while in females they are knobs or no horn at all.
Sumatran Rhinoceros
The Sumatran Rhinoceros (Dicerorhinus sumatrensis) is the smallest extant rhinoceros species, as well as the one with the most fur, which allows it to survive at very high altitudes in Borneo and Sumatra. Due to habitat loss and poaching, its numbers have declined and it is one of the world's rarest mammals. About 275 Sumatran Rhinos are believed to remain.
Typically a mature Sumatran rhino stands about 130 cm (4.3ft) high at the shoulder, a body length of 240315 cm (7.9ft - 10.3ft) and weighs around 700 kg (1543 lbs), though the largest individuals have been known to weigh as much as 1,000 kilograms. Like the African species, it has two horns; the largest is the front (2579 cm) and the smaller being the second, which is usually less than 10 cm long. The males have much larger horns than the females. Hair can range from dense (the most dense hair in young calves) to scarce. The color of these rhinos is reddish brown. The body is short and has stubby legs. They also have a prehensile lip.
Evolution
Rhinocerotoids diverged from other perissodactyls by the early Eocene. Fossils of Hyrachyus eximus found in North America date to this period. This small hornless ancestor resembled a tapir or small horse more than a rhino. Three families, sometimes grouped together as the superfamily Rhinocerotoidea, evolved in the late Eocene: Hyracodontidae, Amynodontidae and Rhinocerotidae.
Hyracodontidae, also known as "running rhinos," showed adaptations for speed, and would have looked more like horses than modern rhinos. The smallest hyracodontids were dog-sized; the largest was Indricotherium, believed to be one of the largest land mammals that ever existed. The hornless Indricotherium was almost seven meters high, ten meters long, and weighed as much as 15 tons. Like a giraffe, it ate leaves from trees. The Hyracodontids spread across Eurasia from the mid-Eocene to early Miocene.
The family Amynodontidae, also known as "aquatic rhinos," dispersed across North America and Eurasia, from the late Eocene to early Oligocene. The amynodontids were hippopotamus-like in their ecology and appearance, inhabiting rivers and lakes, and sharing many of the same adaptations to aquatic life as hippos.
The family of all the modern rhinoceri, the Rhinocerotidae, first appeared in the Late Eocene in Eurasia. The earliest members of Rhinocerotidae were small and numerous; at least 26 genera lived in Eurasia and North America until a wave of extinctions in the middle Oligocene wiped out most of the smaller species. Several independent lineages survived, however. Menoceras, a pig-sized rhinoceros which had two horns side-by-side or the Teleoceras of North America which had short legs and a barrel chest and lived until about 5 million years ago. The last rhinos in America became extinct during the Pliocene.
Modern rhinos are believed to have dispersed from Asia beginning in the Miocene. Two species survived the most recent period of glaciation and inhabited Europe as recently as 10,000 years ago. The Woolly Rhinoceros appeared in China around 1 million years ago and first arrived in Europe around 600,000 years ago and again 200,000 years ago, where alongside the Woolly Mammoth, they became numerous but eventually were hunted to extinction by early humans. Another species of enormous rhino, Elasmotherium, survived the last ice age. Also known as the giant Rhinoceros rhinoceros, Elasmotherium was two meters tall, five meters long and weighed around five tons, with a single enormous horn, hypsodont teeth and long legs for running.
Of the extant rhinoceros species, the Sumatran Rhino is the most archaic, first emerging more than 15 million years ago. The Sumatran Rhino was closely related to the Woolly Rhinoceros, but not to the other modern species. The Indian Rhino and Javan Rhino are closely related and from a more recent lineage of Asian rhino. The ancestors of early Indian and Javan rhino emerged 2-4 million years ago.
The origin of the two living African rhinos can be traced back to the late Miocene species Ceratotherium neumayri. The lineages containing the living species diverged by the early Pliocene , when Diceros praecox, the likely ancestor of the Black Rhinoceros, appears in the fossil record. The black and white rhinoceros remain so closely related that they can still mate and successfully produce offspring.
- Family Rhinocerotidae
- Subfamily Rhinocerotinae
- Tribe Aceratheriini
- Aceratherium
- Acerorhinus
- Alicornops
- Aphelops
- Chilotheridium
- Chilotherium
- Dromoceratherium
- Floridaceras
- Hoploaceratherium
- Mesaceratherium
- Peraceras
- Plesiaceratherium
- Proaceratherium
- Sinorhinus
- Subchilotherium
- Tribe Teleoceratini
- Tribe Rhinocerotini
- Tribe Dicerorhinini
- Tribe Dicerotini
- Subfamily Elasmotheriinae
- Gulfoceras
- Tribe Diceratheriini
- Tribe Elasmotheriini
Predators
In the wild, the adult black or white rhino has no natural predators other than humans but, although it is of massive size and has a reputation of being tough, it is actually very easy to be poached. While visiting water holes daily the rhinoceros is easily killed while taking a drink. As the rhinoceros population is constantly decreasing, efforts are being made to stop the poaching of the rhinos.
Rhinoceros horns
, Tibet, 1938.]] The most obvious distinguishing characteristic of the rhinos is a large horn above the nose. Rhinoceros horns, unlike those of other horned mammals, consist of keratin only and lacks a bony core, such as bovine horns. Rhinoceros horns are used in traditional Asian medicine, and for dagger handles in Yemen and Oman.
One repeated misconception is that rhinoceros horn in powdered form is used as an aphrodisiac in Traditional Chinese Medicine. It is, in fact, prescribed for fevers and convulsions. Discussions with TCM practitioners to reduce its use have met with mixed results since some TCM doctors see rhinoceros horn as a life-saving medicine of better quality than substitutes. China has signed the CITES treaty however. To prevent poaching, in certain areas, rhinos have been tranquilized and their horns removed. Many rhino range States have stockpiles of rhino horn, which needs to be carefully managed.
Historical representations
Albrecht Dόrer created a famous woodcut of a rhinoceros in 1515, without ever seeing the animal depicted. As a result, Dόrer's Rhinoceros is an inaccurate depiction.
There are legends about rhinoceros stamping out fire in Malaysia, India, and Burma. The mythical rhinoceros has a special name in Malay, badak api, where badak means rhinoceros and api means fire. The animal would come when a fire is lit in the forest and stamp it out. There are no recent confirmations of this phenomenon.
Footnotes
External links
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