For the first time in nearly two centuries, giant tortoises are once again roaming Floreana Island in the Galápagos, a conservation milestone more than a decade in the making.
Early settlers on Floreana Island altered the landscape and hunted the Floreana giant tortoise (Chelonoidis niger niger) into extinction about 180 years ago. But while working on Wolf Volcano, roughly 180 kilometers (112 miles) away on Isabela Island, researchers with the Galápagos Conservancy noticed something unexpected.
“The tortoises seemed different,” Penny Becker, CEO of Island Conservation told Mongabay in a video call. “They looked different and they were behaving differently.”
So, the researchers took DNA samples from those tortoises and compared them with DNA from tortoise bones found in caves on Floreana. “Indeed, there were some pretty strong genetics left in the Wolf [Volcano] population from tortoises that were here on Floreana,” Becker said.
How the heavy terrestrial reptiles got to Wolf Volcano remains uncertain. They could have floated on ocean currents or been transported by whaling ships that kept tortoises for food.
In any case, scientists launched a breeding program using the Wolf Volcano tortoises to establish a new hybrid population for reintroduction to Floreana. On Feb. 20, with support from local residents and a consortium of partners, 156 endangered tortoises were released. Each of them is between 10 and 13 years old. They will reach sexual maturity at roughly 25 years old, so building a self-sustaining population will take time.
Becker is confident in the project’s long-term success. The tortoises’ health and progress toward adaptation on the island will be closely monitored. “We’re going to adaptively manage things as we go along to ensure that it’s successful.”
Tortoises are a keystone species and critical ecosystem engineers. Their impacts on the island could be transformative.
“By dispersing seeds, shaping vegetation, creating micro-habitats such as their well-known wallows, and influencing how landscapes regenerate, they help rebuild ecological processes that many other species depend on,” Rakan Zahawi, Charles Darwin Foundation executive director, said in a press release.
Their return is expected to improve seabird nesting habitats, for example. More seabirds mean more nutrients flowing between land and sea, enhancing the so-called “circular seabird economy” that can improve fisheries productivity and coral reef health.
The tortoise reintroduction is part of a much broader restoration effort on Floreana. In 2025 following a successful rat eradication program, the Galápagos rail (Laterallus spilonota), a small ground bird, returned to the island after 190 years. The team is also working on plans to reintroduce several other extirpated species, including the vegetarian finch (Platyspiza crassirostris), one of Darwin’s finches that gave rise to his theory of evolution.
“Seeing giant tortoises return to Floreana confirms that long-term commitment and collective action can restore ecosystems that once seemed lost,” Eliécer Cruz, director of Fundación Jocotoco’s Galápagos Program, said in a press release.
Banner image: A giant tortoise. Image courtesy of Carlos Espinosa via the Charles Darwin Foundation.
This story first appeared on Mongabay
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