100-year-old giant tortoise is credited with rebuilding the population almost single-handed

A sex-mad tortoise which is over 100 years old has single-handedly saved his species from extinction. Diego has fathered 800 babies over the years, turning the tide for his species on the island of Espanola in the Galapagos islands, off the coast of South America.

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

Diego (pictured) gets his name because he was brought to the Galapagos islands from San Diego Zoo in California in the 1960s

Diego is a Chelonoidis hoodensis, a species of Galapagos tortoise found in the wild only on Espanola.

The archipelago in the Pacific Ocean was made famous by Charles Darwin's studies of its breathtaking biodiversity.

Darwin's theories of the survival of the fittest have been underlined by the libidinous Diego who has steered his species back from the brink. 

There were only two males and 12 females on the island 50 years ago before Diego 

Diego now lives at a tortoise breeding centre on nearby Santa Cruz island where he is still mating with his harem of six females.

He weighs 82 kilograms (13 stone) and is nearly 90 centimetres (35 inches) long. 

100-year-old giant tortoise is credited with rebuilding the population almost single-handed