The Giant Tortoise is one of the most recognisable of all the animals of the Galapagos Islands. And, for nature lovers who opt for wildlife holidays in Galapagos, it is one of the most sought-after encounters. As with many other animals, however, despite its iconic status as the world's largest land tortoise, it has faced survival challenges, and today is extinct or near-extinct on some of the islands of the archipelago.
Of an original 14 populations, only eleven remain – with many of them considered critically endangered. The GTRI (Giant Tortoise Restoration Initiative) is a conservation project that aims to turn the tide and restore its populations throughout the islands.
The Work of the GTRI
Established in 2014, the GTRI has been working in partnership with the National Park Directorate to achieve a number of goals. The initiative's long-term goals include:
- - Restoring populations to historical numbers throughout the archipelago. This includes a breeding program to repopulate islands where the endemic subspecies have been rendered extinct.
- - Rejuvenate and restoring habitat where needed.
- - Surveying of current populations to inform future research and conservation efforts.
- - Using advances in genetics to refine future conservation programmes.
Why They Need Help
In an environment where it had no natural predator for millions of years, the Giant Tortoise became the animal that was most affected by human arrival on the islands. For many years, they were used as a food source by settlers and maritime travellers, who worked out that they were able to survive for long periods at sea. They transported them live in the holds of the ships, and then killed them as needed.
In addition to being a food source, the population was decimated with the introduction of animals such as dogs, goats, cows and pigs. Dogs and pigs plundered the eggs and hatchlings, while the cows and goats were in competition for the tortoises’ own food sources.
While it is illegal to capture them today, and introduced animals are gradually being controlled or phased out, in some cases it is too late. But resurrecting an extinct subspecies, such as the one that was endemic to the island of Floreana, is becoming a distinct reality through the dedicated work of the GTRI.
The species from Floreana Island has been considered extinct since 1850. But thanks to advances in DNA testing, scientists were able to determine its exact genetic footprint in 2008. They then tested a hybrid population on the island of Isabela’s Wolf Volcano that had divergent DNA, and discovered that it matched that of the extinct Floreana species. How this crossbreeding occurred is a mystery, although the most likely explanation is through human intervention, perhaps by offloading them between the different islands.
A group of 30 was removed to the research centre on Santa Cruz, where scientists were able to analyse their DNA further. It was discovered that two were classified F1, meaning that they are offspring of two purebred parents. Through a captive breeding programme, the GTRI are now intending to repopulate Floreana Island with the offspring of these animals – effectively bringing the species back from the dead.
Visit the Past and the Future on Wildlife Holidays in Galapagos
Thanks to the GTRI, the species’ past is now linked inextricably to their future, and it looks entirely probable that the population can be restored to its natural habitat. Visitors on wildlife holidays in the Galapagos can visit the Tortoise Centre on Santa Cruz to see the resurrection of the Floreana Giant Tortoise in (albeit very slow) action.
Marissa Ellis-Snow is a freelance nature writer with a special interest in the unique wildlife of the Galapagos Islands. Marissa chooses the expert-led wildlife holidays in Galapagos organised by Naturetrek, which have brought her unforgettable sightings of a wide range of wildlife in one of the most spectacular regions on Earth.