Auburn researchers investigate potential invasion of large, predatory lizards

Published: November 14, 2014
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AUBURN UNIVERSITY – Alabama could potentially be the new home of the Argentine Black and White Tegu, a large predatory lizard reaching 4 feet in length and more than 10 pounds.

The tegus, native to South America, have made their way to southern Florida where they are rapidly flourishing. The lizards are known to eat small mammals, birds and most importantly, other reptile eggs, which presents a threat to alligators and the rare gopher tortoise, both native to the Southeast.

Auburn researchers want to know how far north these invasive lizards can thrive and how much ecological havoc they could bring along with them.

To assess the potential problem, the Alabama Natural Heritage Program, part of the Auburn University Museum of Natural History in the College of Sciences and Mathematics, has taken 19 tegus from South Florida and placed them in artificial habitats in Auburn to observe the lizards throughout the winter.

The project, funded by the United States Geological Survey, will evaluate if the tegus can thrive in the temperate climate of Alabama and if they are capable of reproducing in the spring.

"When an invasive species becomes established, the question always becomes how far is it going to spread," said David Steen, principal investigator of the project and research fellow at the Alabama Natural Heritage Program. "In the past, researchers have used computer models to see how far the range of an invasive species such as the Burmese python might extend, but there is always a lot of uncertainty with those computer models, and they can't replace hands-on experiments where we let the animal show us."

The tegus are contained individually in large tubs, which have been designed to simulate their natural environments.

"We've provided them with cinderblocks covered with tin, sand and pine straw to act as subterranean refuges during the winter," Steen said. "We're feeding the animals a few times a week and basically giving them what they need to survive if they're physiologically able."

Through a collaboration with the Auburn University College of Veterinary Medicine, the tegus have been implanted with both tracking and temperature monitoring devices.

"A primary concern with invasive animals is that they will escape and establish a population. The radio transmitter tracking devices implanted in each of the tegus will allow us to capture them quickly if they were to escape," Steen said. "The temperature monitoring devices helps us understand how the tegus are regulating their body temperatures in response to the changing seasons."

If the tegus survive the winter, Steen will then introduce males and females into the same habitat to evaluate if they can successfully reproduce.

"In the spring, if the tegus reproduce, we will take the eggs, raise them in an incubator and compare the hatching success among different animals," Steen said. "We will then distribute our information and communicate with the Alabama Department of Conservation and Natural Resources to see if tegus are a threat that should be on their radar."

The project is made possible by the United States Geological Survey; Craig Guyer, of the Department of Biological Sciences; Jack Kottwitz, of the College of Veterinary Medicine; Emmett Blankenship, DVM; Jim Godwin of the Natural Heritage Program; Jason Bond, director of the Auburn University Museum of Natural History and undergraduate assistants Joe Jenkins and Charlotte Musser.

For updates on the tegu project and similar research, follow Steend on Twitter @AlongsideWild and view his blog www.LivingAlongsideWildlife.com.

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