Free-ranging reptiles representing dozens of species from around the world are detected in the United States in any given year, usually as a result of escape or illegal release. Fortunately, many of these individuals fail to establish reproductive populations, but all non-native species can potentially pose risks when introduced.
Florida is a major transportation hub and has a climate that’s suitable for many invasive species. As a result, the state has the world’s largest number of established, non-indigenous reptile and amphibian species (3 frogs, 4 turtles, 1 crocodilian, 43 lizards, and 5 snakes). Of the vast number of lizard species, one group of specific concern are tegu lizards because of the threat posed to native fauna. Two species of tegus are now established in Florida - Salvator merianae (Argentine black and white tegu) and Tupinambis teguixin (gold tegu) – and a third has been recorded here— S. rufescens (red tegu). Georgia is the only other state with a confirmed population of Black and white tegus lizards. Tegus have been removed from several counties in Florida and Georgia, and most recently in South Carolina and Alabama, but large portions of the U.S. contain suitable habitat and conditions for tegu lizards.
Green iguanas (Iguana iguana) are another invasive lizard of concern with populations established in Hawaii, Texas, Puerto Rico, and the U.S. Virgin Islands. Green iguanas are known to eat a variety of native plants including plants that are important for endangered species.
Any animal can be problematic when released in places where it is not native. The safest policy is to find an appropriate home for any animal that is no longer wanted because disposal or release in the wild can do great environmental harm.