DNA analysis discovered 17 hybrid tortoises which can trace ancestry to Chelonoidis abingdoni, the species thought to have gone extinct with the death of Lonesome George this summer. (Photo : Yale University)

Lonesome George, the giant tortoise which died this summer on the Galapagos Islands, was thought to be the last known survivor of the species.

Researchers believed that the species Chelonoidis abingdoni became extinct with Lonesome George's death. But this might not be the case as a new study suggests that individual tortoises belonging to the species could possibly be alive.

Researchers from Yale University collected DNA samples from more than 1,600 giant tortoises living in Volcano Wolf, rock cliffs on the remote northern tip of Isabella Island. The island is located some 37 miles away from Pinta Island of which Lonesome George was the last known survivor.

They carried out a genetic analysis on the tortoises and found that 17 tortoises were native to Pinta Island. All 17 tortoises were found to be crossbreeds, but evidence has suggested that some of the species might be the offspring of a purebred C.abingdoni parent, said the researchers.

At least five of the tortoises were found to be juveniles, which suggest that purebred individuals of the species might be living in Volcano Wolf.

Experts believe that the tortoises collected from other islands for food might have been discarded in Volcano Wolf by sailors during the 19th century. Earlier, genetic analysis on the same tortoises showed evidence of tortoises with genetic ancestry of C.elephantopus, a species that once lived in Floreana Island and was hunted to extinction.

Experts suggested that the members of the stranded tortoise species later mated with the native tortoises. They are further planning to collect the hybrids and surviving members of both Pinta and Floreana Island species and start a captive breeding program in order to reinstate the species to their native place. This will help in preserving the evolutionary legacy, said the researchers.

"Our goal is to go back this spring to look for surviving individuals of this species and to collect hybrids," Adalgisa "Gisella" Caccone, senior research scientist from Yale and senior author on the study said in a statement.

"We hope that with a selective breeding program, we can reintroduce this tortoise species to its native home," Caccone said.

The findings of the study are published in the journal Biological Conservation.