Black Rhinoceros
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The Black Rhinoceros (Diceros bicornis; also colloquially, Black Rhino) is a mammal in the order Perissodactyla, native to the eastern and central areas of Africa including Kenya, Tanzania, Cameroon, South Africa, Namibia and Zimbabwe. Like all species of rhinoceros, it is on the endangered species list due to excessive poaching for their horns, which are mostly used in dagger handles as a symbol of wealth in many countries, and as a febrifuge in Chinese traditional medicine. Contrary to popular opinion, only small amounts of the horns are consumed as an aphrodisiac.
An adult Black Rhinoceros stands 1.4–1.7 m high at the shoulder and is anywhere from 3–3.65 m in length. An adult weighs from 800 to 1400 kg, 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. Occasionally, a third smaller horn may develop. Skin colour depends more on local soil conditions and their wallowing behaviour than anything else, so many black rhinos are typically not truly black in colour.
The Black Rhinoceros is slightly smaller than the White Rhinoceros, and has a pointed, prehensile upper lip, which they use to grasp leaves and twigs when feeding. White Rhinoceros have square lips used for grazing grass. The Black Rhinoceros can also be recognized from the White Rhinoceros by its smaller skull and ears and its more pronounced forehead. Black Rhinoceros also do not have a distinguishing shoulder hump like the White Rhinoceros.
The adults are solitary in nature, coming together only for mating. Mating does not have a seasonal pattern but births tend to be towards the end of the rainy season in drier environments. The gestation period is 15–16 months; the single calf weighs about 35–50 kg at birth, and can follow its mother around after just three days. The mother and calf stay together for 2–3 years until the next calf is born; female calves may stay longer, forming small groups. The young are occasionally taken by hyenas and lions. Sexual maturity is reached from 5 years old for females, from 7 years for males, and the life expectancy in natural conditions (without poaching pressure) is from 35–50 years.
Name
Diceros bicornis was dubbed 'Black' Rhinoceros to distinguish it from the 'White' Rhinoceros Ceratotherium simum. This is very misleading, as those two species are not really distinguishable by color. The reason for the misnomer is outlined in C. simum's article.Ecology
The Black Rhinoceros has adapted to its habitat using the following characteristics:- A thick, layered skin protects the rhino from thorns and sharp grasses.
- The soles of their feet are thickly padded to cushion the legs and absorb shock.
- The upper lip has been adapted for seizing and grasping (prehensile) objects which helps in browsing and foraging.
- The large ears rotate to give directional information on sound
- The large nose has an excellent sense of smell to detect predators.
- Two formidable horns are used for defense and intimidation.
- An aggressive disposition discourages predators. The animal's nearsightedness seems to urge the rhino to charge first and investigate later.
Their skin harbours many external parasites, which are eaten by oxpeckers and egrets that live with the rhino.
Subspecies
There are four subspecies of the black rhinoceros:- South-central (Diceros bicornis minor) which are the most numerous, and 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) which had a historic distribution from south Sudan, Ethiopia, Somalia down through Kenya into north-central Tanzania. Today, its range is limited primarily to Tanzania.
- West African (Diceros bicornis longipes) is the rarest and most endangered subspecies. Historically, it once occurred across most of the west African savanna. Until recently, only a few individuals survived in northern Cameroon, but on July 8 2006 the World Conservation Union declared the subspecies to be tentatively extinct. [link]
Population
For most of the 20th century the black rhino was the most numerous of all rhino species. Around 1900 there were probably several hundred thousand [link] living in Africa. During the latter half of the 20th century their number severely reduced from an estimated 70,000 [link] in the late 1960s to only 10,000 to 15,000 in 1981. In the early 1990s the number dipped below 2500, and in 1995 it was reported that only 2,410 black rhinos remained. According to the [International Rhino Foundation], the total African population has since then slightly recovered to 3,610 by 2003. According to a July 2006 report by the World Conservation Union, a recent survey of the West African Black Rhino concluded the subspecies to be extinct.[link]
References and external links
- African Rhino Specialist Group (2003). [Diceros bicornis]. 2006 IUCN Red List of Threatened Species. IUCN 2006. Retrieved on 10 May 2006. Database entry includes justification for why this species is critically endangered
- ARKive - [images and movies of the black rhinoceros (Diceros bicornis)]
- WWF [webpage] about the black rhino.
- Black rhino [entry] on IUCN Red List.
- [Black Rhinoceros] (pdf file)
- [Rhino horn uses]
- Black rhino [fact sheet] on International Rhino Organization website.
- Lincoln Park Zoo [fact Sheet] on the black rhino.
- [U.S. Fish & Wildlife Service Species Profile]
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