Saturday 12 November 2011

The Western Black Rhino and Vietnamese Rhino declared extinct, November 2011.

In November 2011 the Western Black Rhinoceros, Diceros bicornis longpipes, was formally declared extinct by the International Union for Conservation of Nature, in the latest version of the Red List of Threatened Species, the annual publication in which they detail the state of the world's wildlife. This subspecies of the Black Rhino had been classified as Critically Endangered since 2000, when there were an estimated ten animals left in a single population in northern Cameroon. A survey in 2006 failed to locate a single specimen, and, since none have been reported in the intervening time, this year the IUCN took the final step of actually declaring the species extinct. It is thought that the last few animals had been killed by poachers. The last other population, in Chad, was declared extinct in 1990.

The Western Black Rhino, now believed to be extinct.

There are three other subspecies of Black Rhinoceros, the Eastern (D. bicornis michaeli), the South Western (D. bicornis bicornis) and the South Central (D. bicornis minor). All of these are considered to be Critically Endangered, the most severe classification the IUCN gives to species known to have members surviving in the wild. There were estimated to be 700 Eastern Black Rhinoceroses surviving in Kenya and northern Tanzania in 2008. There were thought to be 943 surviving South Western Black Rhinoceroses in 2001, almost entirely in Namibia, but with a few in South Africa where the subspecies has been re-introduced after going extinct. The South Central Black Rhino survives in South Africa, Namibia, Swaziland and southern Tanzania; a 2001 survey put the total population at 1651.

The other species of African Rhino, the White Rhinoceros, has two subspecies. The Southern White Rhinoceros, Ceratotherium simum simum, with an estimated 17 460 surviving individuals across South Africa, Namibia, Botswana, Zimbabwe, Mozambique, Zambia, Kenya and Uganda (in the last three countries it is an introduced species outside of its historical range). The Northern White Rhinoceros, C. simum cottoni (sometimes considered a separate species, C. cottoni), is considered to be extinct in the wild, though there is a captive breeding program at Dvůr Králové Zoo in the Czech Republic, from which there have been attempts to re-introduce animals to Kenya. A report of breeding Northern White Rhinos in Zambia in September 2011 seems unlikely, as this is far from the known historical range of the species.

The Southern White Rhino, now Africa's most widespread Rhinoceros.

All African rhino populations are in severe danger due to poaching. The International Rhino Foundation estimates that 309 rhinos have been killed by poachers so far this year in South Africa alone, despite the fact that South African rhinos are probably the best protected in the world. This is thought to be driven largely by the use of rhino horn in East Asian medicine, which has increased with expanding trade between Africa and the Far East, and has been linked to organized crime in both regions.

A game warden surveys the work of Rhino Poachers in a South African national park.

This year's IUCN Red List also announced the official extinction of the Vietnamese Rhinoceros, Rhinoceros sondaicus annamiticus, a subspecies of the Javan Rhinoceros, reducing the species to a single known population of about 40 individuals of the subspecies R. sondaicus sondaicus in the Ujung Kulon National Park in western Java. Javan Rhinos had been surviving in the Cat Tien National Park in Vietnam, but DNA analysis of dung collected in 2009-10 suggested that only a single individual was surviving. Shortly after this a dead rhino with its horn removed was reported to the WWF in Vietnam, suggesting this subspecies had also fallen to poaching. A third subspecies of Javan Rhino, R. sondaicus inermis, formerly found across Burma (Myanmar) Bangladesh and parts of India, is thought to have gone extinct in the 1920s.

A Javan Rhino at Berlin Zoo.

Like African Rhinos, Asian species have been widely targeted by poachers, and in addition have suffered extensive habitat loss due to deforestation; Asian rhinos tend to inhabit woodland rather than grassland.

The Sumatran Rhinoceros, Dicerorhinus sumatrensis, is now estimated by the International Rhino Foundation to number less than 200 in the wild. Between twelve and twenty five survive in Sabah, Malaysia, belonging to the subspecies D. sumatrensis harrisoni (the Eastern Sumatran or Borneo Rhinoceros). The remainder belong to the subspecies D. sumatrensis sumatrensis, or Western Sumatran Rhinoceros, found in scattered populations in the Gunung Leuser, Way Kambas and Bukit Barisan Seletan National Parks, all on Sumatra. A third subspecies of Sumatran Rhino, D. sumatrensis lasiotis, the Northern Sumatran Rhino, is thought to be extinct. It was formerly found in India, Bangladesh and Burma (Myanmar).

A Sumatran Rhino at Way Kambas National Park in Sumatra.

The third species of Asian Rhino, Rhinoceros unicornis, the Indian or Greater One-Horned Rhino, is found in India and Nepal. There are thought to be about 2800 individuals surviving in the wild. It is listed by the IUCN as Vulnerable, the only species of rhino that is not considered Critically Endangered.

An Indian Rhino at Whipsnade Zoo.

See also A Wooly Rhino from the Pliocene of Tibet and Mammals on Sciency Thoughts YouTube.