December 22, 2010

Researchers Confirm Two Species Of African Elephant

A team of US and UK researchers have used genetic evidence to confirm that there are, in fact, two different species of African elephant, not one as previously believed.

Reporting in the online edition of PLoS Biology, experts from Harvard Medical School, the University of Illinois, and the University of York compared the DNA of modern-day elephants from Asia and Africa against genetic material obtained from the extinct mastodon and wooly mammoth.

By using gene sequencing tools, the scientists were able to determine that the African savannah elephant and the smaller African forest elephant are two separate, distinct species of pachyderms. In fact, according to Julie Steenhuysen of Reuters, the two elephant species have been separated for the most part for at least two million years, and perhaps for as long as seven million years.

"The divergence of the two species took place around the time of the divergence of the Asian elephant and woolly mammoths," York Biology Professor Michi Hofreiter, a specialist when it comes to studying ancient DNA, said in a statement Tuesday. "The split between African savanna and forest elephants is almost as old as the split between humans and chimpanzees. This result amazed us all."

"The surprising finding is that forest and savanna elephants from Africa--which some have argued are the same species--are as distinct from each other as Asian elephants and mammoths," added David Reich, an associate professor in the York biology department.

In addition to the primary discovery, the research was also significant because it was the first time researchers have been able to generate nuclear genome sequences for the mastodon. Furthermore, the study also marked the first time a comparison between all five of these pachyderm species have been analyzed by university researchers at the same time.

While many have long held on to the belief that there was just one species of African elephant, the two different types boast significant differences. According to the researchers, the savannah elephant has an average shoulder height of 3.5 meters and weights between six and seven tons. The forest elephant weighs approximately half of that, and is a full meter shorter at the shoulder.

"We now have to treat the forest and savanna elephants as two different units for conservation purposes," Alfred Roca, and assistant professor in the University of Illinois Department of Animal Sciences, said on Tuesday. "Since 1950, all African elephants have been conserved as one species. Now that we know the forest and savanna elephants are two very distinctive animals, the forest elephant should become a bigger priority for conservation purposes."


Image 1: The savanna elephant weighs between six and seven tons, roughly double the weight of the forest elephant. Credit: A. Schaefer

Image 2: Forest elephants (shown) in Africa have now been confirmed as a new species of elephant and have been distinguished from the larger savanna elephant in Africa. Credit: Nicholas Georgiadis


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