PUERTO AYORA (Ecuador) • He's more than 100 years old, but his sex life is the stuff of legend. Diego the Tortoise is quite the ladies' man, and his exploits have helped save his species from extinction.

Diego, a Galapagos giant tortoise, has fathered an estimated 800 offspring, almost single-handedly rebuilding the species' population on their native island, Espanola, the southernmost in the Galapagos Archipelago.

"He's a very sexually active male reproducer. He's contributed enormously to repopulating the island," said Mr Washington Tapia, a tortoise preservation specialist at Galapagos National Park.

Diego is a Chelonoidis hoodensis, a species found in the wild only on Espanola. The island is one of the oldest in the Galapagos, the Pacific archipelago made famous by Charles Darwin's studies of its breathtaking biodiversity. Around 50 years ago, there were only two males and 12 females of Diego's species alive on Espanola, and they were too spread out to reproduce.

Diego was found at the San Diego Zoo - hence his name - after Chelonoidis hoodensis was identified as a species and an international campaign was launched to find more of the rare tortoises.

He was brought back to the Galapagos in 1976 and put in the captive breeding programme.

He lives at a tortoise breeding centre on Santa Cruz Island, one of the largest in the Galapagos, and is the dominant male of the three assigned to repopulate Espanola.

Weighing about 80kg, nearly 90cm long and 1.5m tall if he really stretches his legs and neck, Diego shares his enclosure with six females, his partners in the task of saving their species. In all, around 2,000 tortoises have been released on the small island. Thanks to the programme, the species is no longer facing extinction.

Not all critically endangered tortoises have risen to the challenge as Diego has done. Hopes for another threatened species, Chelonoidis abingdoni, faded when its last known survivor died in 2012 at more than 100 years old. Known as Lonesome George, he had refused for years to breed in captivity.

AGENCE FRANCE-PRESSE