The Search Is on for a Long-Extinct Giant Tortoise Now 'Seen' in Genetic Footprints

Scientists believe they have found a giant Galapagos Island tortoise thought to have been extinct for the last 150 years. But there's a catch: they haven't actually seen the animal.

So, why are they assuming said tortoise is not still extinct? According to Gizmodo, the DNA from Chelonoidis elephantopus has been showing up in another species of tortoise, C. becki, on the Galapagos Islands. Gizmodo reports that in some cases this tortoise has been revealed as a hybrid, meaning that at least one C. elephantopus could still be alive on the island.

According to Discovery News, Ryan Garrick with the University of Mississippi and his colleagues analyzed DNA of 1,600 tortoise blood samples from Isabela Island and compared it with a genetic database of other tortoises -- living and extinct.

The research by Garrick et al. found 84 hybrid tortoises with DNA that identified them as an immediate descendant of C. elephantopus. Some of these are of an age that indicate the breeding would have taken place in the last 15 years, suggesting a strong likelihood that a reproductively mature C. elephantopus is still alive. Published in Current Biology, the researchers believe this is the first time a once extinct species has been rediscovered using a "genetic footprint".

If a male and female purebred C. elephantopus are found, researchers state they could be bred for reintroduction of the species. If this is the case, the researchers believe that species hybridization is beneficial in that it creates opportunities "to resuscitate imperiled species through targeted breeding efforts."

“This is not just an academic exercise,” Gisella Caccone, senior research scientist in the Department of Ecology and Evolutionary Biology and senior author of the paper, said in a press release. “If we can find these individuals, we can restore them to their island of origin. This is important as these animals are keystone species playing a crucial role in maintaining the ecological integrity of the island communities.”

The search is on.