Mediterranean house geckos making themselves at home at UTC

Mediterranean house gecko

If you’ve ever spotted a pale pink or brown lizard clinging to the wall of a building, or even hiding out in a sink, you’re not alone.

These small reptiles with banded tails and padded toes are Mediterranean house geckos, a non-native species that has quietly made its home in Chattanooga for nearly two decades. This includes many buildings at the University of Tennessee at Chattanooga.

For Nyssa Hunt, assistant director of UTC’s Center for Applied Geospatial Data Science, these geckos first caught her attention on campus about nine years ago. It began as casual sightings, but soon evolved into a long-term project to track where they are living with the help of an online survey.

“I started seeing them as a grad student in 2016,” Hunt said. “But we’ve had reports going back as far as 2007 or 2008. They’re still around—and they are persisting.”

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If you have spotted a Mediterranean house gecko, click here to report the sighting.

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Hunt, who graduated from UTC with bachelor’s and master’s degrees in environmental science, created the survey during her time as a graduate student. With UTC’s GIS resources, she can map where the reptiles appear.

“People have been seeing these geckos all over the place, whether it’s in their house or their dryer. They are even outside my house,” she said. “I’ve heard reports in Soddy Daisy, Hixson, Red Bank, Brainerd, downtown, everywhere.”

The Mediterranean house gecko, true to its name, thrives in built environments.

“They’re mainly found in urban areas because they’re able to exploit these built habitats in a way our native wildlife may not want to or may not be adapted to,” Hunt said. “That’s why they’re called house geckos. They use buildings so much.”

Hunt’s interest in geckos began during her thesis work modeling the habitat preferences of rare native species like the barking tree frog.

For the tree frog, she said the goal was to help preserve its habitat and populations. For the gecko, she wants to understand its habits so that it doesn’t “get as out of control as other invasive species we’ve witnessed.”

Though non-native, the geckos appear to be here to stay. Hunt said they are often found in warmer, humid areas or near sources of water, such as in bathrooms. “It’s safe to say we have viable, surviving populations now,” Hunt said. “They’re finding places to persist during winter even though they’re not freezing-weather tolerant.”

Her former thesis advisor, Dr. Thomas Wilson, noticed the geckos well before Hunt began her graduate work. He recalled his graduate students reporting their findings of the lizards in the mid-2000s.

“They found adults with eggs in the body,” said Wilson, a UC Foundation professor in the Department of Biology, Geology and Environmental Science. “So they’re reproducing. They’re here and they’re surviving.”

Wilson said the geckos likely arrived unintentionally.

“With imported goods, landscapers may bring in mulch, or they might end up in planters or shipments,” he said. “There are probably hundreds of recolonization efforts. Stuff comes in and it gets moved from different metropolitan centers.”

Neither Hunt nor Wilson encourages handling the reptiles. Instead, they recommend simple observation—and, of course, filling out the survey.

“They come into buildings for food, water, or heating and cooling,” Hunt said. “If they got in, they’ll probably get out.”

Now a full-time staff member at UTC, Hunt continues updating the survey and keeping an eye out for new sightings. She hopes to take the research even further.

“I would love to have a firmer understanding of their indoor habitat preferences,” she said. “It’d be great to use ArcGIS Indoors to map out in greater detail where they’re at—and what is it about our buildings that they’re using?”

Hunt and Wilson are also curious how temperature changes might influence the geckos’ spread. Wilson said that future projects could analyze sightings alongside thermal data to see whether climate patterns play a role.

For now, Hunt said she is fascinated by the creatures she’s spent so much of her time studying.

“I’ve been fascinated by them over the years and their little behaviors,” she said. “They continue to confound me, honestly, in what they’re up to. They’re kind of like little dinosaurs.”

And as for what she hopes readers take away from the effort to track them?

“I think we would want them to be recognized and acknowledged that they’re here,” she said. “Just like other animals that we monitor, we would want people to pay attention and continue mapping them. Any information that we can get on wildlife to get a better understanding of our ecosystems will help us to be more conscious stewards of our environment, too.”