Four-Foot-Long Lizards Proliferating in Southeastern U.S.

tegu lizards spreading from florida to as far west as texas

By Jonny Lupsha, Wondrium Staff Writer

Argentine tegu lizards are spreading throughout the southeastern United States, National Geographic reported. The lizards are omnivores, eating smaller animals and fruits, and are the size of dogs, though they can grow up to four feet in length. Reptiles have many unique characteristics.

Tegu lizard in grass
Having been bred for 10 years in Florida, tegu lizards have spread to other states after escaping from captivity or having been released by pet owners. Photo By Arne Beruldsen / Shutterstock

According to National Geographic, a species of lizard is slowly spreading outward from Florida to other states in the region. “The Argentine black-and-white tegu, a large lizard that can grow up to four feet in length, has already proliferated widely throughout South Florida, but it’s not stopping there,” the article said.

“These invaders have started popping up throughout the southeastern United States, posing a potential threat to native species and farmers.”

The article said that the tegu lizards eat everything from other animals’ eggs to other animals. They dine on strawberries and other low-hanging fruit and have been spotted in Georgia, South Carolina, Alabama, Louisiana, and Texas.

Reptiles have many distinct features that separate them from amphibians.

On the Surface

One of the most obvious differences between reptiles and amphibians is their skin.

“Reptiles have dry skin that makes them feel like your dry sneaker, unlike the moist skin of amphibians that makes them vulnerable to dehydration on dry land,” said Dr. Donald E. Moore III, Director of the Oregon Zoo and Senior Science Advisor at the Smithsonian’s National Zoo and Conservation Biology Institute. “A shift away from the amphibian skin’s respiratory function is associated with changes in skin morphology. Unlike the bony, dermally-derived scales we find in fishes, reptile scales are made of keratin from the epidermis.

“The epidermal hard form of keratin in reptile skin that results in their characteristic scales not only makes the skin watertight, it provides protection against wear and tear in the terrestrial environment.”

Dr. Moore said that lizards and snakes have evolved chromatophores in their skin and eyes. Chromatophores are color-bearing cells that give them vibrant colors. However, their skins are sought out for making leather products, which can thin the numbers of certain species.


Dr. Moore said that reptiles have stronger jaws than fish and amphibians. Most reptiles even have bony joints that allow their snouts and upper jaws to move around on their skulls.

“The quadrate bone is the hindmost part of the upper jaw joint, and can move at both its dorsal and ventral extremes; that is, at both the lower jaw and the pterygoid bone, which is part of the palate,” he said. “Even the snout bones can be raised to open the mouth wide, or lowered to maximize bite force between the jaws.”

Dr. Moore also said that both birds and reptiles have two pairs of temporal openings in their skulls, which is known as “the diapsid condition.” In modern lizards, the lower temporal opening is very large and has no lower border, which provides room for the expansion of the large jaw muscles that they use for eating.

“These jaw adaptations have allowed the thousands of reptile species to adapt to different diets, including the mostly vegetarian diets of turtles and tortoises, and the live prey diets of snakes and crocodiles,” he said.

Edited by Angela Shoemaker, Wondrium Daily

Dr. Donald E. Moore, III, Ph.D.

Dr. Donald E. Moore III contributed to this article. Dr. Moore is Director of the Oregon Zoo and Senior Science Advisor at the Smithsonian’s National Zoo and Conservation Biology Institute and a conservation biologist with nearly 40 years of experience in wildlife conservation, animal welfare, and zoo management. He earned a bachelor’s degree in Wildlife Management and Zoology and a doctoral degree in Conservation Biology from the State University of New York College of Environmental Science and Forestry.