Rhinoceroses are killed by poachers for their horns, which are bought and sold on the black market for high prices, leading to most living rhinoceros species being considered endangered. The contemporary market for rhino horn is overwhelmingly driven by China and Vietnam, where it is bought by wealthy consumers to use in traditional Chinese medicine, among other uses. Rhino horns are made of keratin, the same material as hair and fingernails, and there is no good evidence of any health benefits.[3][4][5] A market also exists for rhino horn dagger handles in Yemen, which was the major source of demand for rhino horn in the 1970s and 1980s.[6]
A subspecific hybrid white rhino (Ceratotherium s. simum C. s. cottoni) was bred at the Dvr Krlov Zoo (Zoological Garden Dvur Kralove nad Labem) in the Czech Republic in 1977. Interspecific hybridisation of black and white rhinoceroses has also been confirmed.[10]
Rhino 3dm File Download Free
DOWNLOAD 🔥 https://tiurll.com/2yGckk 🔥
While the black rhinoceros has 84 chromosomes (diploid number, 2N, per cell), all other rhinoceros species have 82 chromosomes. Chromosomal polymorphism might lead to varying chromosome counts. For instance, in a study there were three northern white rhinoceroses with 81 chromosomes.[11]
The name "black rhinoceros" (Diceros bicornis) was chosen to distinguish this species from the white rhinoceros (Ceratotherium simum). This can be confusing, as the two species are not truly distinguishable by color. 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 occidentalis) 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 declared extinct in November 2011.[14] The native Tswanan name keitloa describes a South African variation of the black rhino in which the posterior horn is equal to or longer than the anterior horn.[15]
During the latter half of the 20th century, their numbers were severely reduced from an estimated 70,000[18] in the late 1960s to a record low of 2,410 in 1995. Since then, numbers have been steadily increasing at a continental level with numbers doubling to 4,880 by the end of 2010.[citation needed] As of 2008, the numbers are still 90% lower than three generations ago.[19]
Indian rhinos once inhabited many areas ranging from Pakistan to Myanmar and maybe even parts of China. Because of humans, they now exist in only several protected areas of India (in Assam, West Bengal, and a few pairs in Uttar Pradesh) and Nepal, plus a pair in Lal Suhanra National Park in Pakistan reintroduced there from Nepal. They are confined to the tall grasslands and forests in the foothills of the Himalayas. Two-thirds of the world's Indian rhinoceroses are now confined to the Kaziranga National Park situated in the Golaghat district of Assam, India.[22]
The Sumatran rhinoceros (Dicerorhinus sumatrensis) is the smallest extant rhinoceros species, as well as the one with the most hair. It can be found at very high altitudes in Borneo and Sumatra. Because of habitat loss and poaching, their numbers have declined, and it has become the second most threatened rhinoceros. About 275 Sumatran rhinos are believed to remain. There are three subspecies of Sumatran rhinoceros: the Sumatran rhinoceros proper (Dicerorhinus sumatrensis sumatrensis), the Bornean rhinoceros (Dicerorhinus sumatrensis harrissoni) and the possibly extinct Northern Sumatran rhinoceros (Dicerorhinus sumatrensis lasiotis).
Sumatran rhinoceros once were spread across South-east Asia, but now are on the verge of extinction, confined to several parts of Indonesia and Malaysia by reproductive isolation. There were 320 D. sumatrensis in 1995, which, by 2011, had dwindled to 216[citation needed]. It has been found through DNA comparison that the Sumatran rhinoceros is the most ancient extant rhinoceros and related to the extinct Eurasian woolly rhino species, Coelodonta. In 1994 Alan Rabinowitz publicly denounced governments, non-governmental organizations, and other institutions for lacking in their attempts to conserve the Sumatran rhinoceros. To conserve it, they would have to relocate them from small forests to breeding programs that could monitor their breeding success. To boost reproduction, the Malaysian and Indonesian governments could also agree to exchange the gametes of the Sumatran and (smaller) Bornean subspecies. The Indonesian and Malaysian governments have also proposed a single management unit for these two ancient subspecies.[30][31]
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. Four families, sometimes grouped together as the superfamily Rhinocerotoidea, evolved in the late Eocene, namely the Hyracodontidae, Amynodontidae, Paraceratheriidae 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. Hyracodontids spread across Eurasia from the mid-Eocene to early Oligocene.
The 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 Paraceratheriidae, also known as paraceratheres or indricotheres, originated in the Eocene epoch and lived until the early Miocene. The first paraceratheres were only about the size of large dogs, growing progressively larger in the late Eocene and Oligocene. The largest genus of the family was Paraceratherium, which was more than twice as heavy as a bull African elephant, and was one of the largest land mammals that ever lived.
The family of all 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. Menoceras, a pig-sized rhinoceros, had two horns side by side. The North American Teleoceras had short legs, a barrel chest and lived until about five million years ago. The last rhinos in the Americas became extinct during the Pliocene.
Modern rhinos are thought to have begun dispersal from Asia during the Miocene. Alongside the extant species, four additional species of rhinoceros survived into the Last Glacial Period: the woolly rhinoceros (Coelodonta antiquitatis), Elasmotherium sibiricum and two species of Stephanorhinus, Merck's rhinoceros (Stephanorhinus kirchbergensis) and the Narrow-nosed rhinoceros (Stephanorhinus hemitoechus).[34] The woolly rhinoceros appeared in China around 1 million years ago and first arrived in Europe around 600,000 years ago. It reappeared 200,000 years ago, alongside the woolly mammoth, and became numerous. 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. The latest known well dated bones of Elasmotheriumin found in the south of Western Siberia (the area that is today Kazakhstan) date as recently as 39,000 years ago.[35]
The origin of the two living African rhinos can be traced to the late Miocene (6 mya) 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.[36] The black and white rhinoceros remain so closely related that they can still mate and successfully produce offspring.[10]
Although rhinos are large and aggressive and have a reputation for being resilient, they are very easily poached; they visit water holes daily and can be easily killed while they drink. As of December 2009, poaching increased globally while efforts to protect the rhino are considered increasingly ineffective. The most serious estimate, that only 3% of poachers are successfully countered, is reported of Zimbabwe, while Nepal has largely avoided the crisis.[56] Poachers have become more sophisticated. South African officials have called for urgent action against poaching after poachers killed the last female rhino in the Krugersdorp Game Reserve near Johannesburg.[57] Statistics from South African National Parks show that 333 rhinoceroses were killed in South Africa in 2010,[58] increasing to 668 by 2012,[59] over 1,004 in 2013,[60][61][62] and over 1,338 killed in 2015.[63] In some cases rhinos are tranquilized and their horns removed leaving them to bleed to death, while in other instances more than the horn is taken.[64]
The Namibian government has supported the practice of rhino trophy hunting as a way to raise money for conservation. Hunting licenses for five Namibian Black rhinos are auctioned annually, with the money going to the government's Game Products Trust Fund. Some conservationists and members of the public oppose or question this practice.[65]
Rhinoceros horns are used in traditional medicines in parts of Asia, and for dagger handles in Yemen and Oman. Esmond Bradley Martin has reported on the trade for dagger handles in Yemen.[69] In Europe, it was historically believed that rhino horns could purify water and could detect poisoned liquids, and likely believed to be an aphrodisiac and an antidote to poison.[70] 152ee80cbc
download series open bo episode 7