Rhinoceros, black
Узнай больше о нашей работе
Классификация:
Общая Численность
Описание И Естественная История
Physical DescriptionRhinoceroses (from the Greek, "nose horn") are named for their most distinctive feature, the single or double horn on the end of the nose.
Of the five species of rhinoceros, the white (Ceratotherium simum) and black (Diceros bicornis) rhinoceroses of Africa, and the Sumatran rhinoceros (Dicerorhinus sumatrensis) have two horns in tandem, while the Indian (Rhinoceros unicornis) and Javan (Dicerorhinus sondaicus) have only one.
In the black rhino, the larger front horn measures 0.5 – 1.3 meters (16 – 52 inches) in length. Rhinos are massive animals with a large head, short neck, broad chest, thick skin and short stout legs. Each foot has three toes, which leave a cloverleaf-shaped footprint.
The black rhino is actually gray, although the color varies from yellow-brown to dark-brown depending on the color of the local soil. Adult males and females are about the same size, weighing 800 – 1,350 kilograms (1,750 – 3,000 pounds) and measuring 1.4 –1.7 meters (4.5 – 5.5 feet) at the shoulder.
The black rhino has a prehensile (adapted for seizing or grasping) upper lip that it uses for grasping branch ends, and from which it gets the name "hooked-lipped rhino."
Rhinos have a poor sense of sight but a good sense of hearing and a keen sense of smell. The testes of the male do not descend into the scrotum as with most mammals, and females have one pair of teats between their back legs.
Calves are born weighing about 40 kilograms (88 pounds) and have a pink hue to their color that fades to gray as they age.
Natural History
There are four subspecies of black rhinoceros; the southern-central black rhino (D.b. minor), the south-western black rhino (D.b. bicornis), the east African black rhino (D.b. michaeli) and the west African black rhino (D.b. longipes).
Historically, the four subspecies inhabited different areas throughout sub-Saharan Africa, except for the tropical forest of the Congo Basin.
Today, their distribution has been radically affected by hunting and habitat loss, and now only patchily distributed animals survive within guarded game reserves and private parks.
The black rhinoceros lacks incisors and canine teeth. Instead, it uses the upper lip to grasp woody plants, along with some forbs (herbs other than grass) and fruits.
Black rhinoceroses depend on water almost daily but can go for up to five days without a visit to the watering hole. They are often found wallowing in the water holes, coating themselves in mud to help protect against biting insects.
Adult male black rhinos are usually solitary except during mating, and adult females are also found alone except for mothers with calves. Adults of both sexes, however, may join up to form pairs or larger groups for short periods of time. Adult males have vicious fights with each other for receptive females. They have the highest incidence of death from fighting of any mammal.
Female black rhinos reach sexual maturity between four and seven years of age. Males reach sexual maturity between seven and eight years of age but do not attain dominant status until closer to ten years.
A single calf is born every two to four years, although the calving interval may be as short as 22 months. Most calves are born during the dry season and are weaned at about one year of age. They are driven away by the mother between two and three years of age just prior to the birth of her next offspring.
Статус Вида
StatusThe black rhino is listed as Critically Endangered by the International Union for the Conservation of Nature and Natural Resources (IUCN).
It is also listed on Appendix 1 of the Convention on International Trade of Endangered Species of Wild Fauna and Flora (CITES), which makes it illegal to import or export black rhino products. The black rhino is also protected under national wildlife legislation, although enforcement varies in the different range states.
Threats to the Species
Historically, black rhinos were hunted by settlers and big-game hunters, which reduced their numbers during the colonial era.
From 1970 through the 1990s, black rhinos were intensely poached and their numbers plummeted from an estimated 100,000 individuals to fewer than 3,000.
Protection under CITES in the 1970s proved ineffectual and numbers continued to decline. Horns were sold on the black market to Arab countries (particularly North Yemen) where they were crafted into dagger handles and worn by men as status symbols.
Asia also provided a large black market for rhino horn where it was ground up for use in traditional medicines. While it remains illegal to kill black rhinoceroses, poachers continue to kill them to fill the demand created by the market for traditional medicines and decorative Arab dagger handles. Continued poverty in Africa has fueled the illegal trade in rhino horn, and wildlife departments have little or no funding or support to stop it.
Poaching increases during times of civil unrest and Angola, Chad, Mozambique, Somalia, Sudan and other African countries have been involved in civil wars over the past 30 years. Along with politics and poverty, corruption, ignorance and the availability of weapons (from civil wars) have had significant negative impacts on rhino populations.
Today, virtually all black rhinoceros populations exist within small, fenced areas under armed protection. The continuation of such protection is costly; many parks depend on tourist dollars to support their activities. Efforts to curb poaching have included the involvement of local villagers so that they can benefit directly from conservation (e.g. employment in protection or ecotourism), instituting education programs, hiring more guards, and moving individual rhinos to safer areas.
More controversial efforts have included shooting poachers on sight and de-horning animals so that they no longer have value in the marketplace.
Some so-called "wise use" groups propose making wildlife (including rhinos) pay for itself by allowing trophy hunting of males, the sale of individual animals in the marketplace, and the harvesting of rhino horn for limited legal trade. Placing value on rhino and other wildlife, however, virtually assures that poaching and illegal trade will continue to flourish.
Low rhino populations, particularly in specific areas, raise the question of how to solve the long-term problem of genetic bottlenecks and overcrowding.
The most recent population estimate of 1998 suggests that about 2,600 black rhinoceroses survive in Africa. Populations have shown modest increases since the mid-1990s due to increased protection in South Africa.
International Trade
Listed on CITES Appendix I which prohibits international trade.
Автор и Источники
SourcesCITES. 2001. Diceros bicornis. www.cites.org
IUCN. 2001. The 2000 IUCN Red List of Threatened Species. http://www.redlist.org.
WWF. Black rhinoceros. www.panda.org.
WCMC and WWF International. October 1999. Black rhinoceros threatened species account. www.panda.org.
Owen-Smith, N. and J. Berger. 2001. Rhinoceroses. Pg 477-481 In MacDonald, D. (Ed). The New Encyclopedia of Mammals. Oxford University Press, Oxfordshire, UK.
;)
| |||||
 |
