Thursday 16 March 2017

Scientists Identify Four Species of Giraffes

In general, new plants, animals, and other forms of life are discovered in two ways, either by being stumbled across in the wild (or somewhere else “outside”) or through laboratory work that results in reshuffling standing species classifications. News of a freshly minted species discovered in the wild tends to be a bit more exciting than those discovered in a laboratory; however, when laboratory work involves what ecologists call “charismatic megafauna” and the research results in a dramatic shift in our understanding, the news can be very exciting.
Take the humble giraffe—the towering, long-necked, cud-chewing, African hoofed mammal of Africa. For many people, the giraffe was one of the first animals they recognized as a child. Was it the giraffe’s awkward form that first entranced us, or was it the unusual blotchy pattern of its coat?
Historically, most scientists have placed all giraffes into one species, Giraffa camelopardalis, and nine officially recognized subspecies; however, a new genetic study released this week conducted by German and Namibian scientists has separated these animals into four species. The researchers examined DNA strands in giraffe mitochondria from the nine formal subspecies as well as the Nubian giraffe. Their analysis revealed that the lack of breeding between various groups of giraffes over the past 1.25 million to 2 million years produced genetic differences between them. The researchers identified four distinct giraffe clades (biological groupings of taxa, each of which includes all of the descendants of one common ancestor), and they considered each clade a distinct species.
As one might expect, the four different species of giraffes were also separated from one another by geography. 
  1. Northern giraffes (G. camelopardalis) are found in pockets from northern Cameroon and southern Chad to South Sudan and western Ethiopia.
  2. southern giraffes (G. giraffa) live across large swaths of Namibia, northern Botswana, southern Zimbabwe, and the northern fringe of South Africa.
  3. Masai giraffes (G. tippelskirchi) are found in East Africa from southern Kenya to eastern Zambia.
  4. reticulated giraffes (G. reticulata) are primarily concentrated in Kenya.

The ripples of this new giraffe taxonomy are expected to radiate beyond species classification manuals and into giraffe conservation. The International Union for Conservation of Nature (IUCN) currently acknowledges a single giraffe species, Giraffa camelopardalis, and considers it a species of least concern. The division of giraffes into four species, combined with reports of the number of giraffes declining from 140,000–150,000 animals to 80,000–90,000 animals within 30 years, suggests that environmental organizations and governments will take notice. Perhaps four species of giraffes could do what only one species could not—that is, give the countries that host giraffe populations reasons to create additional antipoaching laws and to more closely examine threats to giraffe habitat.

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