By LISSA STROHECKER

Maui Invasive Species Committee

Between the chirp of the house gecko snatching insects by the window or the flash of color on the lanai as a gold dust day gecko scurries past, lizards are commonplace around homes and yards in Hawaii. Eighteen species of geckos, skinks, and chameleons now reside in Hawaii. Relegated to the status of a tropical trinket, scientists haven’t paid much attention to them. Half of these arrive here since 1950, Most arrived in the last few decades, hitchhiking on landscape material or escaping from the pet trade. Conventional wisdom is that these lizards couldn’t have made it to the islands independently – it’s too far for something lacking wings or flippers.

Of those eighteen non-flying, non-swimming reptiles, three skinks have been in Hawaii for hundreds of years. “Excavations and records of Western explorers show they were here before Western contact,” says Valentina Alvarez. She completed her PhD dissertation at the University of Hawaii exploring the genetics of these lizards.

Hawaiian stories and olelo (sayings) reference mo’o – lizards. Since these three skink species are common elsewhere in the Pacific, scientists assumed they’d arrived with the Polynesians, carried in canoes along with ulu and coconut, chickens and dogs.

But building on decades of observation from her colleagues, Alvarez suspects that during the millions of years that the Hawaiian archipelago has existed, a particularly hardy skink could have floated here on debris, surviving because it was adapted to life on the coastline. “There are little bits of evidence here and there,” Alvarez says, “but the strongest evidence lies in the genetics of the lizards.”

The snake-eyed skinks found in Hawaii are related to an old lineage, distinct from other populations of this species in the Pacific, she explains. The differences imply that Hawaii’s snake-eyed skinks may have arrived tens of thousands or even millions of years ago. “That’s not the pattern with the two other skinks present before Western contact,” Alvarez says. These other two skinks are genetically very similar to existing populations elsewhere in the Pacific.

The snake-eyed skink, scientific name Cryptoblepharus poecilopleurus, also fits the profile of a potential pioneer. Alvarez says the evidence indicates it’s tolerant of saltwater. Adapted to life along salt-sprayed coastlines and in hot, rocky habitats, the skink is physically predisposed to surviving an ocean voyage. The genus also has a track record: close relatives of the snake-eyed skink have made it to other remote islands in the Polynesian triangle (defined by the three island groups at its corners–Hawaii, Rapa Nui (Easter Island), and Aotearoa (New Zealand)). “A subspecies of this lizard on Rapa Nui is thought to have naturally colonized the island. Like Hawaii, Rapa Nui is super remote,” she explains.

For further proof, Alvarez is looking deeper into the genetics across the Pacific to see if she can narrow down the potential arrival period of the snake-eyed skink. “We’ll see if we can make that distinction to see if the snake-eyed skink arrived before the first human arrival,” she says.

One challenge is finding skinks today. Along with the other “canoe lizards” (the azure-tailed skink and the moth skink) populations of the snake-eyed skink are shrinking. In the 1840s, Western explorers declared them “as common as leaves on a tree.” Now Alvarez has trouble finding them. “The populations are very fragmented and when I do find them, they’re in low abundance.” Along a stretch of beach that would be a suitable habitat, she might find three or four. “I’ve never met another person who has seen one that doesn’t already study lizards.” The cause of their decline is likely the combination of disturbance, invasive species like ants, and competition with introduced lizards.

The most robust populations are away from people. Laysan Island in the northwest Hawaiian Islands and a tiny islet off the coast of Oahu are two of the few places where snake-eyed skinks are thriving, but otherwise, all that’s left of these ancient lizards are a handful of scattered populations.

You can help in the efforts to find out more about the snake-eyed skink–Hawaii’s first mo’o. Alvarez relies on iNaturalist, the online citizen science platform, to find lizard populations. If you’re exploring a rocky coastline and see a dark-colored skink sprinkled with gold, try to snap a picture and share it through iNaturalist.com. The lizard is skittish, but according to Alvarez, waiting quietly will encourage it to return. Reporting other lizard species through the iNaturalist platform can also help researchers find and track their distribution and spread.

As always, reports of snakes should go to 911 for immediate response. Illegally-owned reptiles can be turned in without penalty through the Hawaii Department of Agriculture’s amnesty program – no questions asked.

* Lissa Strohecker is the public relations and education specialist for the Maui Invasive Species Committee. She holds a biological sciences degree from Montana State University. Kia’i Moku, “Guarding the Island,” is prepared by the Maui Invasive Species Committee to provide information on protecting the island from invasive plants and animals that can threaten the island’s environment, economy, and quality of life.