Small, Secretive Gecko Rediscovered in the Galápagos After Scientists Eliminate Invasive Rats

Researchers thought leaf-toed geckos were locally extinct on Rábida Island, so they were thrilled to find several of the lizards alive and well during 2019 and 2021 expeditions

Sarah Kuta | Daily Correspondent

July 29, 2025

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A small, elusive lizard is bouncing back following the eradication of invasive rats on an island in the Galápagos.

Conservationists say they have rediscovered a leaf-toed gecko (Phyllodactylus maresi) on Rábida Island, a small, hilly outpost in the middle of the famed archipelago in the eastern Pacific Ocean. They thought the tiny, land-dwelling creatures were locally extinct, so they were overjoyed to find several members of the species alive and well during expeditions on Rábida Island in 2019 and 2021.

Scientists describe the mysterious reptile’s reappearance in a June 13 paper published in the journal PLOS ONE.

Leaf-toed geckos are secretive and petite, with adults measuring a little more than three inches long, reports New Scientist’s Graeme Green. For decades, researchers thought the nocturnal lizards had died out on Rábida Island before humans discovered the Galápagos in the early 16th century. The only proof the geckos had ever lived on the island came from fossilized remains that were between 5,700 and 8,540 years old, the researchers write in the paper.

Meanwhile, rats were introduced to Rábida at some point within the last 50 years and began decimating the island’s native plants, birds and reptiles. If any elusive leaf-toed geckos were still hiding out somewhere on the island, the arrival of the invasive rodents likely left little hope for their survival.

But in 2011, conservationists decided to take aim at the rats with an eradication project. The California-based nonprofit Island Conservation, along with Galápagos National Park, the Charles Darwin Foundation and the Raptor Center, dropped poisoned rat bait from helicopters onto several islands in the Galápagos.

The project was a success on Rábida. And the removal of the invasive rodents, it seems, gave the geckos a boost. In 2012, biologists found a single leaf-toed gecko on the island. They photographed and collected the creature for further study, however, at some point, that specimen went missing.

In October 2019, scientists returned to Rábida Island to search for more leaf-toed geckos. They found nine of them and took tissue samples from their tails before releasing them back into the wild. In August 2021, they visited the island again and collected the bodies of ten leaf-toed geckos for further study.

Subsequent analyses of the lizards’ anatomy and DNA confirmed the their identities as leaf-toed geckos.

“We conducted extensive monitoring prior to the removal of invasive rats, and [leaf-toed geckos] weren’t detected at all,” study co-author Paula Castaño, impact program manager with Island Conservation, tells New Scientist. “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. You can call it one of the most historic comebacks ever or just a long-overdue reappearance.”

Genetic testing also revealed the lizards living on Rábida are closely related to those of the same species living on nearby islands, but still distinct enough to be considered their own lineage.

More broadly, the research on leaf-toed geckos “underscores the critical value of collecting specimens and genomic samples for both scientific discovery and conservation efforts in the Galápagos,” says lead author Omar Torres-Carvajal, reptile curator at Pontifical Catholic University of Ecuador’s QCAZ Museum of Zoology, in an Island Conservation statement.

“This archipelago still holds hidden surprises, waiting to be discovered,” he adds.

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Sarah Kuta is a writer and editor based in Longmont, Colorado. She covers history, science, travel, food and beverage, sustainability, economics and other topics.