Diego the tortoise was just doing his Darwinian duty.

Tortoise in the Galapagos
Credit: RODRIGO BUENDIA/AFP/Getty Images

With little more than a healthy sexual appetite and some good luck, Diego the tortoise may have saved his near-extinct species in the Galapagos Islands.

At more than 100 years old, this strapping tortoise has fathered 800 offspring, effectively bringing the species back from extinction, Agence-France Presse reported.

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

Named Diego for the San Diego Zoo where he once lived, this lothario tortoise was originally born on the island of Espanola, where his Chelonoidis hoodensis species is one of 15 giant tortoise species.

Diego was returned to his home in the Galapagos in 1976 as part of a scheme to repopulate the island. He lives in an enclosure with six females and has served his biological duty, bringing the species back from the brink.

Populations of giant tortoises were first severely depleted in the 19th century by passing whaling ships. Throughout the 20th century the numbers continued to dwindle after predators such as pigs, dogs, cats and rats were introduced to the islands, according to a Galapagos travel guide.

Tortoises were also hunted for their oil and for their shells, which became collectors’ items.

A conservation effort has been underway to protect the remaining giant tortoises since the mid-20th century, including the creation of enclosed habitats and breeding schemes.