These ‘vigorous little tortoises’ are the future of their species on a Galápagos island

For the first time in more than 180 years, giant tortoises are roaming Floreana Island in Ecuador’s Galápagos archipelago. 

Last week, scientists and local park rangers released 158 juvenile hybrids onto the Galápagos island — once home to an estimated 20,000 giant tortoises — thanks to a captive “back breeding” program that started in 2017. Whalers, a catastrophic fire and relentless human exploitation drove the Floreana tortoise to extinction on the archipelago’s southernmost island in the 1840s.

For conservation biologist James Gibbs, the moment felt much like watching his children take their first steps.

“They’re very vigorous little tortoises, eager to get out of their containers … and immediately started exploring their new homes,” Gibbs, vice-president of science and conservation at the Galápagos Conservancy, told As It Happens host Nil Köksal.

The young tortoises, which Gibbs says will grow up to 600 pounds in the next 10 to 20 years, are out of a total of 700 planned to be released gradually in Floreana. According to Christina Sevilla, director of ecosystems of the Galapagos National Park, the juveniles carry between 40 per cent to 80 per cent of the genetic makeup of the Chelonoidis niger — the extinct Floreana species.

“In genetic terms, reintroducing a species to that island with a significant genetic component of the original species is vital,” biologist Washington Tapia told the Associated Press.

Tapia, a researcher and director of Biodiversa-Consultores — a firm specializing in the Galapagos Island — stressed that the initiative is about more than just boosting numbers, but rebuilding a lost lineage.

The hope is that the 158 newcomers — aged eight to 13 and weighing between 30 to 50 pounds — will help to restore the island’s depleted ecosystem over time, especially given that their lifespans can exceed more than a century. 

The release 

You could say the release was a labour of love. Gibbs says he and the other park rangers carried the hefty juveniles off the ship, on their backs, trudging up the slopes of the volcanic island in sweltering heat before reaching the secure release sites, where they opened the crates and watched the tortoises amble into the wild.

“We divided the … 158 into two groups, one of 50 to go into a drier area in the lowland part of the island and another big group of 108 to go up into slightly moister highlands,” said Gibbs, adding that he expects many will eventually drift toward the highland farmlands, where foliage is richer and water sources are more abundant.

The newcomers now share Floreana Island with about 200 people, as well as flamingos, iguanas, penguins, gulls and hawks. They must also contend with non-native species introduced by humans — rats, cats, pigs and donkeys — along with plants such as blackberry and guava, all of which pose potential threats to the island’s newest inhabitants.

“They are large enough to be released and can defend themselves against introduced animals such as rats and cats,” said Fredy Villalba, director of the Galapagos National Park breeding centre on Santa Cruz Island.

Even though they’ve left their shelled charges behind, Gibbs says the team will still be keeping an eye on them. Each of the tortoises have been fitted with tiny GPS trackers, allowing researchers to monitor their movements in real time. 

“We’ve been looking at them every hour and seeing they’re all heading out together in pairs and trios,” he said. “These tags will go for another 10 years or so … if any of them stop moving, we’ll go out and check on them … but we’re just kind of monitoring them quietly and seeing that they’re settling in quite nicely into their new home — or old home.”