|The rhinoceros or rhino, is any of five surviving species of odd-toed ungulates in the family Rhinocerotidae. Two species are native to Africa and three to southern Asia. One of the five species is endangered, and another, the Indian Rhinoceros, is endangered.
The family is characterized by large size (one of the few remaining megafauna surviving today) with all of the species capable of reaching 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 its horn. 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, but the horn is not itself made of hair as some have believed. Rhinoceros also have acute hearing and sense of smell, but poor eyesight. Most rhinoceros live to be about 50 years old or more. The collective noun for a group of rhinoceros is "crash".
Both African species and the Sumatran Rhinoceros have two horns, while the Indian and Javan Rhinoceros have a single horn.
Taxonomy and naming
The word "rhinoceros" (ρινόκερος) is derived from the Greek words rhino, meaning nose, and kera, meaning horn; hence "horned-nose". The plural can be rhinoceros, rhinoceri, rhinoceroses, or rhinoceroi. A group of rhinos is called a crash.
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 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. The name White Rhinoceros was actually a mistake, or rather a corruption of the word wijd (wide in Afrikaans) because of 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 sub specific hybrid white rhino (Ceratotherium s. simum × C. s. cottoni) was bred at the Dvůr Králové Zoo (Zoological Garden Dvur Kralove nad Labem) in the Czech Republic in 1977. Interspecific hybridization 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.
The White Rhinoceros or Square-lipped rhinoceros (Ceratotherium simum) is one of the five species of rhinoceros that still exist and is one of the few megafauna species left. Behind the elephant, it is probably the most massive remaining land animal in the world, along with the Indian Rhinoceros which is of comparable size. It is well known for its wide mouth used for grazing and for being the most social of all rhino species. The White Rhino is the most common of all rhinos and consists of two subspecies, with the northern subspecies being rarer than the southern. The northern subspecies may have as few as 50 remaining world wide.
A popular theory of the origins of the name White Rhinoceros is a mistranslation from Afrikaans. The Afrikaans word "wyd" (derived from the Dutch word "wijd"), which means "wide", referred to the width of the Rhinoceros mouth. Early English settlers in South Africa misinterpreted the "wyd" for "white". So the rhino with the wide mouth ended up being called the White Rhino and the other one, with the narrow pointed mouth, was called the Black Rhinoceros. This explanation is thought to be somewhat implausible. A review of Dutch and Afrikaans literature about the rhinoceros, however, has failed to produce any evidence that the word wyd was ever used to describe the rhino.
An alternative common name for the white rhinoceros, more accurate but rarely used, is the square-lipped rhinoceros. The White Rhinoceros' generic name, Ceratotherium, is derived from the Greek terms keras "horn" and therion "beast". The specific epithet, simum, is derived from the Greek term simus, meaning "flat nosed".
The name of the species was chosen to distinguish it from the White Rhinoceros (Ceratotherium simum). This is 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.
An adult Black Rhinoceros stands 147-160 cm (57.9-63 inches) high at the shoulder and is 3.3-3.6 m (10.8-11.8 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.
The Indian Rhinoceros or the Great One-horned Rhinoceros (Rhinoceros unicornis) is found in Nepal and in Assam, India. The rhino once inhabited areas from 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 northeastern India and Nepal. 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. Its size is comparable to that of the White Rhino in Africa. Fully grown males are larger than females in the wild, weighing from 2200–3000 kg (4,800-6,600 lb). Female Indian rhinos weigh about 1600 kg. The Indian Rhino is from 5.7–6.7 feet tall and can be up to 13 feet 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.
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 vigina, 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 1930's the rhinoceros was nearly hunted to extinction in India, Burma, Peninsular Malaysia, and Sumatra for the 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 1.5–1.7 m tall. Adults are variously reported to weigh between 900-1,400 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.
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 300 Sumatran Rhinos are believed to remain.
Typically a mature Sumatran rhino stands about 130 cm high at the shoulder, a body length of 240–315 cm and weighs around 700 kg, 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 (25–79 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 are reddish brown. The body is short and has stubby legs. They also have a prehensile lip.
Rhinocerotoids first diverged from other Perissodactyls in at least the Early Eocene. Fossils of Hyrachus eximus found in North America date to this period. This small ancestor resembled a tapir or small horse, more than a rhino, and had no horn. Three families, sometimes grouped together as the superfamily Rhinocerotoidea, evolved in the Late Eocene: Hyracodontidae, Amynodontidae and Rhinocerotidae.
Hyracontidae, also known as "running rhinos," showed adaptations for speed, and would have looked more like horses than modern rhinos. The smallest Hyracontidae were dog-sized; the largest was Indricotherium, believed to be the largest land-mammal that ever existed. The hornless Indricotherium was almost six meters high, nine meters long, and weighed as much as 20 tons. Like a giraffe, it ate leaves from trees. The Hyracontids spread across Eurasia from the mid-Eocene to early Miocene.
The Amynodontidae family, 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 rhinoceroses, 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 Teloeceras 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.
Modren 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 unicorn 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 lineage of rhinos in Africa is less clear. The black and white rhinoceros remain so closely related that they can still mate and successfully produce offspring. The black rhinoceros is believed to be the oldest of the species, first emerging between 4 and 10 million years ago, and the white rhinoceros diverging from within the black rhinos between 2 and 5 million years ago.
- Kingdom: Animalia
- Phylum: Chordata
- Class: Mammalia
- Order: Perissodactyla
- Family: Rhinocerotidae Gray, 1821
- Family Rhinocerotidae
- Subfamily Rhinocerotinae
- Tribe Aceratheriini
- Aceratherium (extinct)
- Acerorhinus (extinct)
- Alicornops (extinct)
- Aphelops (extinct)
- Chilotheridium (extinct)
- Chilotherium (extinct)
- Dromoceratherium (extinct)
- Floridaceras (extinct)
- Hoploaceratherium (extinct)
- Mesaceratherium (extinct)
- Peraceras (extinct)
- Plesiaceratherium (extinct)
- Proaceratherium (extinct)
- Sinorhinus (extinct)
- Subchilotherium (extinct)
- Tribe Teleoceratini
- Aprotodon (extinct)
- Brachydiceratherium (extinct)
- Brachypodella (extinct)
- Brachypotherium (extinct)
- Diaceratherium (extinct)
- Prosantorhinus (extinct)
- Shennongtherium (extinct)
- Teleoceras (extinct)
- Tribe Rhinocerotini
- Gaindatherium (extinct)
- Rhinoceros - Indian & Javan Rhinoceros
- Tribe Dicerorhinini
- Coelodonta - Woolly Rhinoceros (extinct)
- Dicerorhinus - Sumatran Rhinoceros
- Dihoplus (extinct)
- Lartetotherium (extinct)
- Stephanorhinus (extinct)
- Tribe Ceratotheriini
- Ceratotherium - White Rhinoceros
- Tribe Dicerotini
- Diceros - Black Rhinoceros
- Paradiceros (extinct)
- Subfamily Elasmotheriinae
- Gulfoceras (extinct)
- Tribe Diceratheriini
- Diceratherium (extinct)
- Subhyracodon (extinct)
- Tribe Elasmotheriini
- Bugtirhinus (extinct)
- Caementodon (extinct)
- Elasmotherium - Giant Unicorn (extinct)
- Hispanotherium (extinct)
- Huaqingtherium (extinct)
- Iranotherium (extinct)
- Kenyatherium (extinct)
- Menoceras (extinct)
- Ougandatherium (extinct)
- Parelasmotherium (extinct)
- Procoelodonta (extinct)
- Sinotherium (extinct)
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 fallacy 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 tranquillized and their horns removed.
Cultural depictions of rhinos
There are a number of legends about rhinoceroses stamping out fire. The story seems to have been common in Malaysia, India, and Burma. This type of rhinoceros even had 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. Whether or not there is any truth to this has not yet been proven, as there has been no documented sighting of this phenomenon in recent history. This lack of evidence may stem from the fact that rhinoceros sightings overall in south-east Asia have become very rare, largely due to widespread poaching of the critically endangered animal. This legend is featured prominently in the film The Gods Must Be Crazy as well as on an episode of The Simpsons.
Although rhinos are herbivores, in the novel James and the Giant Peach by author Roald Dahl, the main character's parents are supposedly eaten by a rhinoceros that had escaped from the London Zoo.
Albrecht Dürer created a famous woodcut of a rhinoceros in 1515, without ever seeing the animal depicted. As a result, Dürer's Rhinoceros is rather inaccurate.