Cameleopard - Taxonomy and Evolution - Subspecies

Subspecies

Up to nine subspecies of giraffe are recognized (with population estimates as of 2010):

  • G. c. camelopardalis, the nominate subspecies, is known as the Nubian giraffe. It is found in eastern South Sudan and south-western Ethiopia. Fewer than 250 are thought to remain in the wild, although this number is uncertain. It is rare in captivity, although a group is kept at Al Ain Zoo in the United Arab Emirates. In 2003, this group numbered 14.
  • G. c. reticulata, known as the reticulated or Somali giraffe, is native to north-eastern Kenya, southern Ethiopia and Somalia. It is estimated that no more than 5,000 remain in the wild, and based on International Species Information System records, more than 450 are kept in zoos.
  • G. c. angolensis, the Angolan or Namibian giraffe, is found in northern Namibia, south-western Zambia, Botswana and western Zimbabwe. A 2009 genetic study on this subspecies suggests that the northern Namib Desert and Etosha National Park populations form a separate subspecies. It is estimated that no more than 20,000 remain in the wild; and approximately 20 are kept in zoos.
  • G. c. antiquorum, the Kordofan giraffe, has a distribution which includes southern Chad, the Central African Republic, northern Cameroon and north-eastern DR Congo. Populations in Cameroon were formerly included in G. c. peralta, but this was incorrect. No more than 3,000 are believed to remain in the wild. Considerable confusion has existed over the status of this subspecies and G. c. peralta in zoos. In 2007 it was shown that all alleged G. c. peralta in European zoos were, in fact, G. c. antiquorum. With this correction approximately 65 are kept in zoos.
  • G. c. tippelskirchi, known as the Masai or Kilimanjaro giraffe, can be found in central and southern Kenya and in Tanzania. It is estimated that no more than 40,000 remain in the wild, and approximately 100 are kept in zoos.
  • G. c. rothschildi is known variously as the Rothschild, Baringo or Ugandan giraffe. Its range includes parts of Uganda and Kenya. Its presence in South Sudan is uncertain. Fewer than 700 are believed to remain in the wild, and more than 450 are kept in zoos.
  • G. c. giraffa, the South African giraffe, is found in northern South Africa, southern Botswana, southern Zimbabwe and south-western Mozambique. It is estimated that no more than 12,000 remain in the wild, and approximately 45 are kept in zoos.
  • G. c. thornicrofti, called the Thornicroft or Rhodesian giraffe, is restricted to the Luangwa Valley in eastern Zambia. No more than 1,500 remain in the wild, with none kept in zoos.
  • G. c. peralta, commonly known as the West African, Niger or Nigerian giraffe, is endemic to south-western Niger. Fewer than 220 individuals remain in the wild. Giraffes in Cameroon were formerly believed to belong to this subspecies, but are actually G. c. antiquorum. This error resulted in some confusion over its status in zoos, but in 2007 it was established that all "G. c. peralta" kept in European zoos actually are G. c. antiquorum.

Giraffe subspecies are distinguished by their coat patterns. The reticulated and Masai giraffe represent two extremes of giraffe patch shapes. The former has neatly shaped patches while the latter has jagged ones. There are also differences in the width of the lines separating the patches. The West African giraffe has thick lines while the Nubian and reticulated giraffe have thin ones. The former also has a lighter coat pelage than other subspecies.

A 2007 study on the genetics of six subspecies—the West African, Rothschild, reticulated, Masai, Angolan and South African giraffe—suggests that they may in fact be separate species. The study deduced from genetic drift in nuclear and mitochondrial DNA (mtDNA) that giraffes from these populations are reproductively isolated and rarely interbreed, even though no natural obstacles block their mutual access. This includes adjacent populations of Rothschild, reticulated and Masai giraffes. The Masai giraffe may also consist of a few species separated by the Rift Valley. Reticulated and Masai giraffes have the highest mtDNA diversity, which is consistent with the fact that giraffes originated in eastern Africa. Populations further north evolved from the former while those to the south evolved from the latter. Giraffes appear to select mates of the same coat type, which are imprinted on them as calves. The implications of these findings for the conservation of giraffes were summarised by David Brown, lead author of the study, who told BBC News: "Lumping all giraffes into one species obscures the reality that some kinds of giraffe are on the brink. Some of these populations number only a few hundred individuals and need immediate protection."

The West African giraffe is more closely related to the Rothchild and reticulated giraffe than to the Kordofan giraffe. Its ancestor may have migrated from eastern to northern Africa and then to its current range with the development of the Sahara desert. At its largest, Lake Chad may have acted as a barrier between West African and Kordofan giraffes during the Holocene.

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