(CNN) A womanizing tortoise whose rampant sex life may have single-handedly saved his entire species from extinction has retired from his playboy lifestyle, returning to the wild with his mission accomplished.

Diego's unstoppable libido was credited as a major reason for the survival of his fellow giant tortoises on Espanola, part of the Galapagos Islands, after being shipped over from the San Diego Zoo as part of a breeding program.

When he started his campaign of promiscuity, there were just two males and 12 females of his species alive on the island.

But the desirable shell-dweller had so much sex he helped boost the population to over 2,000. The Galapagos National Parks service believe the 100-year-old tortoise is the patriarch of around 40% of that population.

"He's contributed a large percentage to the lineage that we are returning to Espanola," Jorge Carrion, the park's director, told AFP. "There's a feeling of happiness to have the possibility of returning that tortoise to his natural state."

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