One of the species of giant tortoises found on the Galapagos Islands which was believed to have become extinct around 150 years ago is still alive and well, with around 84 hybrid members living on a volcano on Isabela Island.
There are 13 types of giant tortoise associated with the islands, where Charles Darwin came to his conclusions about evolution. This particular tortoise is called Chelonoidis elephantopus and was thought to have died out shortly after Darwin's stay on the islands in 1835. The Galapagos Islands are off the coast of Ecuador in South America and are famous for the amazing variety of flora and fauna species found only there and nowhere else in the world.
According to a report on Jan 9 in the Daily Telegraph, researchers from Yale University have been studying the DNA of tortoises they found on Isabela island and found that of the 2,000 specimens, the genetic material of 84 of them showed they must have had a pure bred C. elephantopus parent. The giant tortoises were found living among a different species called Chelonoidis becki. Previous scientific research on museum specimens had led the researchers to head out to the Galapagos to look for live specimens.
The tortoises can live for over a 100 years but 30 of the hybrids were less than 15 years old which, the scientists believe, means that pure bred tortoises are still alive.
USA Today reports that the tortoises had originally lived on Floreana Island, where there are definitely none of the species left alive after they were hunted to extinction by whalers looking for food. Adalgisa Caccone, who is an evolutionary biologist at Yale University and senior author on the paper published Jan 9 said:
"The only way these hybrids could be produced is if we had some pure Floreana animals still alive on the island… because some of these animals are hybrids which are first-generation crosses,"
A further expedition is planned for December 2012 to look for the pure bred tortoises, some of whom may have actually been seen by Darwin due to their longevity.