This Once-Rare Lizard Bounced Back From the Brink of Extinction After ‘Painstaking’ Restoration Efforts in the Caribbean

A “cheeky and charismatic” lizard found only on a small Caribbean island has bounced back from the brink of extinction, according to a new survey.

Biologists are celebrating the recovery of the Sombrero ground lizard (Pholidoscelis corvinus), a critically endangered reptile that’s endemic to Sombrero Island—meaning it can’t be found anywhere else on Earth. And, just years ago, the creature had been nearly wiped out from its home.

The species’ population had dwindled to fewer than 100 individuals in 2018. But, thanks to targeted conservation efforts, more than 1,600 of the scaly, black-blue reptiles are now scampering across the arid, limestone island. The nonprofit conservation group Flora & Fauna announced the latest numbers this week, in partnership with the Anguilla National Trust and Re:wild.

“We were absolutely ecstatic when we analyzed the results of our population surveys and found this enormous increase in their numbers,” says Farah Mukhida, the executive director of Anguilla National Trust, to Popular Science’s Laura Baisas.

Sombrero Island is a rocky, uninhabited outpost located roughly 34 miles northwest of Anguilla. The 94-acre island is situated within the Anegada Passage, a channel between the Caribbean Sea and the Atlantic Ocean. It’s home to the remains of an old lighthouse, as well as a newer lighthouse that was automated in 2001, reports National Park Traveler’s Jennifer Bain.

Despite its diminutive size, the island provides habitat for many creatures—including brown boobies, the Sombrero Island bee, a pygmy gecko and the Sombrero Island wind scorpion. Migratory birds stop at the island in the spring and fall, and several species breed there, including sooty terns and laughing gulls. The waters surrounding the island also support coral reefs, sargassum and seaweed; endangered green sea turtles often visit to forage.

Starting in the 1800s, however, American and British miners began flocking to Sombrero Island to take advantage of its abundant seabird guano, which can be used as fertilizer. In the process, they introduced invasive mice and ravaged the ecosystem. The island was once covered in trees and even had its own endemic giant tortoise species—but it was pillaged to the point of being nothing more than a “barren moonscape,” wrote the Guardian’s Patrick Greenfield in 2022.

“Sombrero Island has been so degraded by human activity that it no longer looks like a hat to approaching sailors,” per the Guardian.

More recently, devastating hurricanes have further damaged Sombrero Island, and such storms in 2018 led the ground lizard’s population to crash. The whole island was “on the verge of ecological collapse,” according to a statement from Flora & Fauna.

But since 2021, conservation groups have been working to reintroduce native plants and remove the invasive mice. “The past three years have seen painstaking restoration activity,” Mukhida says in the statement. That type of work is “not an easy feat on such a remote and rocky island.”

Now, their efforts are paying off: The island is considered pest-free and is brimming with green plants like sea bean, seagrape and prickly pear. And as for the Sombrero ground lizards, their numbers have ballooned by 16 times in six years.

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The island isn’t the lush, tree-covered landscape it once was—that will likely take years. But conservationists are hopeful that within the next decade or so, they’ll be able to build the soil back up enough to support trees and bushes, per the Guardian.

Conservationists say their work is important not only to protect the island’s animals now, but also into the future. Sombrero Island, which has a maximum elevation of 39 feet, is susceptible to new threats with climate change, including sea-level rise, higher temperatures, more intense storms and longer droughts—and so are Sombrero ground lizards.

“Already there are reports that the island … has been completely inundated by storm surges from major hurricanes, and modelling indicates that the frequency and intensity of hurricanes in the Caribbean will continue to increase,” according to the International Union for Conservation of Nature.

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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.