After decades of solitude, "Lonesome George" may finally save his species of Galapagos giant tortoise from extinction, his keepers said on Monday.

George, a Pinta island tortoise who has shown little interest in reproducing during 36 years in captivity, stunned his keepers by mating with one of his two female companions of a similar species of Galapagos tortoise.

Park rangers found a nest with several eggs in George's pen and placed three in incubators. It will take about four months to know whether the eggs bear George's offspring.

"Even if these three eggs are fertile and the born tortoises survive it will take several (genetic) generations to think of having a Pinta purebred ... even centuries," the park said in a statement.

After trying almost everything from artificial insemination to having George watch younger males mate, his keepers had nearly lost hope. At 60 to 90 years old, George is in his sexual prime and should be able to reproduce.

Scientists found a distant relative of George on another island last year, sparking hopes of another male for mating with some Pinta genes.

The visual differences of tortoises from different islands were among the features of the Galapagos that helped British naturalist Charles Darwin formulate his theory of evolution.

George, considered by many the world's rarest creature and a conservation icon, was thought to be the last of his kind after fishermen and pirates slaughtered his species for food.

Ecuador has declared the islands at risk and the United Nations says efforts to protect them should continue. Some 20,000 giant tortoises of various species now live on the islands.