'Extinct' Gecko Rediscovered After Rat Removal

A species of tiny and secretive geckos long thought lost on one Galápagos island has made a dramatic return, and all it really took was calling someone about the rat problem. NewScientist reports that conservationists rediscovered the elusive leaf-toed gecko on Rábida Island—a small, hilly isle overrun by invasive rats about 50 years ago. The last anyone had seen of the shy, three-inch reptiles on the island was in fossil form from between 5,700 and 8,450 years old—until researchers spotted live ones during expeditions in 2019 and 2021. Study co-author Paula Castaño said, "You can call it one of the most historic comebacks ever or just a long-overdue reappearance."

The study asserts it likely has to do with a bold rat-eradication campaign in 2011 in which helicopters dropped poisoned bait on Rábida and 10 other islands in the Galapagos as part of a multi-agency effort to give native reptiles, birds, and plants a fighting chance. The next year, a lone leaf-toed gecko surprisingly turned up on Rábida, but it vanished before researchers could get their hands on it. Then nine were found in 2019, followed by 10 more in 2021. DNA confirmed their identity and revealed the survivors were not the same as similar geckos found on nearby islands. "We conducted extensive monitoring prior to the removal of invasive rats, and [leaf-toed geckos] weren't detected at all," said Castaño. "We believe a small population held on all those years and then, without invasive predators, it finally had the opportunity to recover and grow its population."

The Smithsonian reports lead study author Omar Torres-Carvajal said this all should be proof that it's of "critical value" to collect specimens in the Galapagos for conservation efforts. "This archipelago still holds hidden surprises, waiting to be discovered." Because this shy gecko actually isn't the only species to reemerge on Rábida since the restoration campaign: "We found the 'extinct' gecko, rediscovered a snail last seen in 1906, as well as two other snail species being recorded on the island for the first time ever that are still being identified, and Galápagos hawks have returned and are thriving," said Castaño. "Nature is remarkable—allow it an opportunity to thrive, and it comes roaring back."