Investigating an Invasion
Georgia Southern students, faculty research invasive lizard species
A creature docile enough to be a house pet yet invasive enough to destroy an ecosystem is posing a major threat to the woodlands of southeast Georgia.
But faculty and student researchers in the Department of Biology at Georgia Southern University are working with state and federal partners to locate and eradicate this creature, the Argentine black and white tegu — an invasive lizard species that preys on native and threatened wildlife like gopher tortoises, and that could possibly wreak havoc on regional crops through bacterial contamination.
Lance McBrayer, Ph.D., lizard expert and associate dean of research in the College of Science and Mathematics, has partnered with the Georgia Department of Natural Resources (DNR) and the U.S. Geological Society to educate the public on tegus and to capture and study these creatures to determine the effects they are having on the area. While it is unclear how the lizards arrived in Toombs and Tattnall counties in Georgia, female tegus can lay up to 40 eggs at once, meaning the population can increase very quickly.
“Tegus have been a problem in south Florida for 20 years or more, and it was thought that they might spread,” McBrayer said. “Georgia was the first place we saw tegus other than in Florida, and now they have been found and trapped in South Carolina. We have caught the tegus early in their invasion here in Georgia, so we’re hopeful that we can eradicate them or at least keep their numbers here way down.”
McBrayer and a few student researchers have captured around 20 tegus, which can grow to be more than three or four feet in length and weigh up to 10 pounds, since beginning the project in 2019. Students get hands-on research experience by setting and monitoring traps, then collecting data on the lizards after they are captured. Students study the health conditions of the tegus to determine if they carry parasites and, if so, whether those parasites could affect native wildlife.
“This project is important on so many levels,” McBrayer said. “Not only are there potential economic impacts on agricultural products and impacts on our native wildlife that we are working to prevent, but many of our biology students also desire careers with the Georgia DNR or other federal agencies. This project gives them first-hand experience and knowledge of how removing an invasive species works. They get a lot of really valuable experience that you just can’t get in a classroom setting.”
As they capture more tegus, McBrayer and his students will study the reproductive system. They are also studying the use of capsaicin — red pepper oils — on the bait used to capture tegus.
“The hope is that we can deter small mammals like possums and raccoons from going into or disturbing the trap because they don’t like the taste of capsaicin,” he said. “Reptiles don’t generally have those receptors, so they’re undeterred.”
McBrayer has studied tegus since the ’90s, and says they are popular among exotic pet enthusiasts. As a pet, these lizards can be calm, intelligent and can be adaptable when properly trained.
“I’ve even seen pictures online of people walking them around on leashes,” McBrayer said with a laugh. “They can be pretty adaptable, but it takes a very responsible pet owner to handle the animal frequently in order to get the animal to settle down.”
But once in the wild, tegus will eat just about anything, McBrayer said.
“Once they are back in the wild, they really quickly adapt to what they evolved to do, and that is walk around, eat just about anything and dig burrows,” he said.
Tegus are known to find gopher tortoise burrows, which harbor lots of other diversity, McBrayer said, noting the lizards are highly efficient predators.
“Tegus dig up gopher tortoise eggs and eat them, and they eat eggs and hatchlings of ground-nesting birds like turkey or quail,” he said. “They also eat fruits and vegetables, frogs and small lizards, small snakes and lots of bugs.”
In Florida, tegus are commonly found around agricultural fields, which leads to concerns of tegus disturbing peanut, onion or vegetable crops in Georgia, he added.
“The biggest concern is that we have a unique and valuable native wildlife fauna, so if tegu numbers increase, then this would have negative impacts on our native wildlife,” he said.
Although tegus pose a threat to the landscape of Georgia, wildlife and potentially agricultural crops, they aren’t really a danger for humans, McBrayer noted. But, that doesn’t mean they’re ready for human interaction in the wild.
“I would say in 99% of human encounters that a tegu lizard is going to run away very quickly or they’re just going to look at the person and keep their distance and keep on walking,” he said. “If a person were to corner one and try and grab one and handle it, tegus have very powerful jaws and sharp teeth, so you would very likely get bitten and may need stitches or be bruised up.”
McBrayer said invasive species are not protected in any way, so the DNR does not discourage the animals from being legally taken or removed, though animal cruelty and local ordinances do apply. Sightings can also be reported at GeorgiaInvasives.org. — Crissie Elrick Bath