After a five-hour journey by boat and an inland journey on a ranger´s backpack, Diego, the giant tortoise who helped save his species from extinction, finally arrived his native Española Island, in the emblematic Ecuadorian archipelago of Galápagos.
Diego, now over 100 years old, will have the chance to live in the wild after eight decades of residing in a zoo and in a conservation center, where he fathered at least 800 offspring.
On June 15, the Galápagos National Park organized the release into the wild of Diego and other 14 giant tortoises, which had been part of a breeding programme that started in the 60s to recover the Chelonoidis hoodensis population in Española Island, where the species had dropped to only 15 specimens.
The project was based on Santa Cruz, another island in the archipelago. Diego and two other males, plus 12 females took part in the recovery project, with such a success that now Española holds a stable population of around 2,300 tortoises.
Renowned for his fertility, Diego stood out for his charismatic personality. His caregivers describe him as being very active and vocal in his mating habits. When the Park announced in 2016 that he had fathered at least 40% of all the young tortoises in Española, he went viral.
Diego lived in the San Diego Zoo for around 30 years and came back to Galápagos in 1976. His impressive journey has caught worldwide attention. “Diego´s efforts helped us bring back a species that was on the brink of extinction. Diego´s legacy is along us to move forward”, said Freddy Villalba, a park ranger.
14 species of giant tortoises populated the Galápagos Islands, famous for inspiring Charles Darwin´s theories of evolution and natural selection.
Three species have been officially declared extinct: Chelonoidis abingdonii (Pinta Island), Chelonoidis niger (Floreana Island) and Chelonoidis phantasticus (Fernandina Island). One specimen of the latter might have been found, but genetic tests are still being developed to confirm the discovery.
Diego and his 14 companions bred in captivity for more than 40 decades. They were kept in two corrals, where scientists gathered the eggs and kept them in incubators. Once the tortoises were born, they stayed at the recovery center for seven years before they were released back to Española Island. This method lasted until 2012. In 2018, the last juveniles were transported to Española.
“With no doubt the Española breeding programme is a conservation success story since we were able to restore this population with only 15 individuals. We have now detected natural reproduction in the island and we are ready to shut the programme down”, said Danny Rueda, director of the Galápagos National Park.
The Ministry of Environment of Ecuador decided to end the breeding program, after a 2019 census in Española found that the island had sufficient conditions to maintain the tortoise population, which will continue to grow normally, even without new repatriations of juveniles. The survey was conducted by the Galápagos National Park Directorate and Galápagos Conservancy, as part of the Giant Tortoise Restoration Initiative.
“The survival rate of the young tortoises is over 50 percent”, said Rueda, who emphasizes that the breeding programme was accompanied by ecosystem restoration measures.
“With so few tortoises for so long, the Española ecosystem dynamics had changed. In the 70s we eradicated the goats, that were introduced in the 17th century by pirates and whalers. Eight years ago we started reintroducing cactus and other plant species that are essential to the tortoises´ diet”, said Rueda.
Diego and the other 14 tortoises were transported by park rangers 2,5 kilometers towards the island´s interior where there is abundant cactus. The females weigh around 35 kilograms, while the males weigh 55 kilograms. All are between 80 and 100 years old. They will be monitored by GPS trackers and 40 camera traps. Free at last, but closely watched by the rangers that have taken care of them for so long, Diego and his companions will be able to wander around their home island.