Native to Brazil, Paraguay, Uruguay and Argentina, the tegu lizard's acidic stomach dissolves bones and shells, meaning they leave little trace of the prey they consume. Some tegu species reach up to four feet in length.
Biologists with the Florida Fish and Wildlife Conservation Commission (FWC) say they've spotted more than 100 tegus in habitat surrounding the Tampa area.
"People buy these cute little lizards at the pet store and then they grow to be too big for an aquarium and they are too expensive to feed and then they just set them free in the preserves," FWC biologist Tessie Offner told local news channel WTSP.
"They produce rapidly, laying between 25-50 eggs at a time," said Offner. "They eat everything from plants to other animals with bones and shells- also amphibians, and birds."
Breeding populations of tegus have now been discovered in three Florida counties -- Miami-Dade, Hillsborough and Polk. The lizards have no known predators in Florida.