Chicago: Instead of one species of elephant, Africa has two, researchers said on Tuesday, confirming suspicions about the two distinctly different looking pachyderms.
Using gene sequencing tools, teams from Harvard, the University of Illinois and the University of York in Britain have shown that instead of being the same species -- as scientists have long believed -- the African savanna elephant and the smaller African forest elephant are distant cousins, having been largely separated for 2 million to 7 million years.
"What our study suggests is forest and savanna elephants are very distantly related to each other and not just subspecies or populations of the same species," said Alfred Roca of the University of Illinois, who worked on the study published in the Public Library of Science journal PLoS Biology.
The teams compared the genetic code of modern elephants from Africa and Asia to DNA taken from two extinct species -- the woolly mammoth and the American mastodon.
"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," David Reich of Harvard Medical School in Boston, who worked on the study, said in a statement.
Africa`s forest and savanna elephants are vastly different in size. The savanna elephant is roughly double the weight of the forest elephant at six to seven tons and measures about 11.5 feet tall at the shoulder -- about 3 feet (1 meter) taller than the forest elephant.
Even so, many scientists had thought the two populations of elephants came from the same species, in part because they mated and produced offspring.
Not so, says Professor Michi Hofreiter, an expert in ancient DNA from York.
"The divergence of the two species took place around the time of the divergence of the Asian elephant and woolly mammoths," Hofreiter said in a statement.
"The split between African savanna and forest elephants is almost as old as the split between humans and chimpanzees.
"This result amazed us all."
Roca said comparing the genetic sequence of the mastodon -- a very distant cousin of the other species -- allowed the researchers to see where in evolution the elephants split.
"The forest and savanna elephants proved to be as genetically distinct from each other as the woolly mammoth from the Asian elephant," Roca said in a telephone interview.
On a practical basis, the study means that conservationists will need to think about the two species differently.
"For the last 50 years, all African elephants have been treated as the same species. In fact, they are so different you really have to come up with a different conservation plan for each of the two," Roca said.