The Rarest Creature on Earth

This is an unusual case: scientists know that a species is extinct even if its last individual has not died yet. But it could still exist for 1-2 centuries more. This is the "Lonesome George", the last known survivor of a species of Pinta tortoise, one of the 13 species of giant tortoises (of which two are already extinct) found in the Galapagos archipelago off Ecuador. Pinta is one of the islands of the archipelago.

Many say the effort to fend off extinction may be useless. Even if a partner is found, George has not shown interest in reproducing with females in his pen at the Darwin Research Center and may not know how. Even when other males were kept with the females in the pen, George did not get the idea.

"The search is a long shot. George may be physiologically incapable of reproducing." said Linda Cayot, a science adviser for the Galapagos Conservancy and former keeper of George.

"He has problems ... he probably never saw a female and male of his own species reproducing," said Swiss biologist Sveva Grigioni, who worked with George 13 years ago.

The precise age of George is not known; the age of the 5ft-long (1.5 meter) giant, weighing 200lb (90.7 kg) is estimated between 60 to 90. George was officially proclaimed the rarest creature on Earth according to The Guinness Book Of Records.

Still, earlier this year, a team at Yale University in Connecticut found a male tortoise on the island of Isabela (another Galapagos island) that was the hybrid between a Pinta male and an Isabela female. Thus, more Pinta tortoises could be found on Isabela.

George could live till 200 and still reproduce, if he learns how to do it. He was found on Pinta in 1971.

Since the discovery of the Galapagos islands in 1535, the tortoises have been hunted by sailors for meat (live tortoises could be kept for months on the shipboard, providing fresh meat) and the goats introduced in the islands degraded tortoises' environment and competed with them for food.

Today, there are some 20,000 giant tortoises living in the archipelago, belonging to 10 species.