Critically endangered giant tortoises released in Galapagos Islands


A group of 191 critically endangered Hood Island giant tortoises has been released in the Galapagos Islands to replace a species that went extinct 150 years ago because of whale hunters and pirates.

The tortoises belong to the Chelonoidis hoodensis species, which are critically endangered according to the IUCN’s Red List. They were released on the 25-square-kilometre (9.6-square-mile) Galapagos island of Santa Fe in Ecuador.

The tortoises were bred in captivity at the Fausto Llerena centre on the nearby island of Santa Cruz, as part of a programme to restore the ecological balance of the island of Santa Fe. There used to be tortoises from a similar species on Santa Fe too but the endemic population went extinct 150 years ago due to whale hunters and pirates.

The new batch of tortoises belong to the Chelonoidis hoodensis, which are endemic to Espanola island and according to Christian Sevilla, a technician at the National Park, they are the most genetically similar to the ones that once lived on Santa Fe.

The group of tortoises is the final phase of a lengthy reintroduction process of giant tortoises to the island that started in 2015 and is geared towards repopulating it with this species.

Washington Tapia, director of the Programme for the Restoration of Giant Tortoises, said that as it was impossible to find the endemic tortoise of the Santa Fe island, it was decided to use the ones living on Espanola island, because they are “analogous to the species that once lived there”.

He also said most of the animals released in this final phase of the programme are young and it is difficult to know how many are female or males but “they were incubated so that most of them would be females”.

A tortoise’s gender is determined by the temperature during the egg’s incubation, so if the eggs are incubated at 28 degrees Celsius, more males hatch, but if they are incubated at 29.5 degrees Celsius, more females are born.

In this group, there are also 31 tortoises that are nearly adults, of which 14 are male and the rest are female, and they will reach sexual maturity soon.

These new tortoises had to undergo a quarantine process of 10 weeks in order to eliminate any seeds in their digestive system. The animals also had parasites removed and underwent a health check. They also had a microchip put in, in order to be identified in the future.

With this new group, there are now 732 giant tortoises on the island, closely watched over by the national park’s guards. They will pay special attention to their reading, but according to Tapia: “We believe that with what we have released it is enough for the island.”

Tapia also said that it was important have a “breeding population on the island” as this “contributes to the restoration of the ecological integrity and biodiversity on Santa Fe.”

The Director of the National Park, Danny Rueda, said that the ecological process began in the 1970s, when the goats that had been introduced on the island were eradicated, as they were a real problem for the survival of the tortoises as they ate the vegetation that the tortoises depended on for food.

The tortoises will live with other animals on the island, such as iguanas and 18 bird species. They play an important role in the ecosystem. Tapia explained: “They play the same role as large mammal, controlling vegetation and spreading seeds, which helps to preserve the correct balance in the ecosystem.”

Tapia added: “We have managed to give Santa Fe the key piece it needs.”

One of the most famous Hood island giant tortoises in the Galapagos is Diego, a 100-year-old tortoise which helped to keep the species alive by single handedly fathering about 40 percent of the 2,000 tortoises present in the islands since the beginning of the breeding programme in the 1960s.

It is unclear which of the latest tortoises to be introduced to the island are his descendants.