Recently on Isabela Island in the Galapagos, Scientists did DNA testing on over 1,600 tortoises and found at least 84 of them who were the direct offspring of a different tortoise species from nearby Floreana Island that was long believed to be extinct. What they found was amazing, that a few survivors of a giant Galapagos tortoise species thought to have gone extinct in the 1840s may still exist today.

The Galapago's giant tortoises gained noteriety as one of the species that helped Charles Darwin develop his theory of evolution. In 1835 Darwin discovered that many of the islands in the remote Pacific islands west of Ecuador were home to their own, distinct, tortoise species. Each one differed slightly from those on nearby islands. It was his theory of evolution that helped to explain how each species had evolved to survive best in it's home island. The Chelonoidis Elephantopus was one of the species of Tortoise that Darwin found living on Floreana Island. But within a decade after his expedition left, the whalers had killed them all off for food.

Or so they thought. On the expedition this time, scientists took blood samples from 1,669 tortoises, which is about 20% of the island's population. What they found when they took the blood samples back to the lab was that out of the 1,669 samples, 84 were Floreana/Isabela hybrid individuals. At least 30 of the hybrids were less than 15 years old so the matings were recent. The only way these hybrids could be produced was if there were some pure Floreana animals still alive on the island, because some of these tortoises are hybrids which are first-generation crosses.

Although the researchers didn't actually find any pure blooded tortoises on this trip, the evidence of the hybrids is that they are still there and reproducing. The researchers plan to hold a workshop this year in the Galapagos to discuss what can be done now. Then in December of 2012 they plan to send an expedition back to look for the pure Floreana tortoises. The giant tortoises are crucial to the ecosystems of their islands, because the highly endangered prickly pear cactus that grows on them can only sprout after its seeds have gone through the gut of one of the tortoises.

The other really fascinating fact from this discovery is that when they do find the pure blooded tortoises that are living on Isabela Island, they could possibly be the offspring of the ones Darwin saw. This is because this species of the giant tortoise is known to live to 100 years and beyond. Therefore the direct offspring of animals alive in 1840 could still be alive.