Massive, voracious lizards are invading the southwest of the U.S.

Invasive black and white tegu lizard (Salvator merianae). The USGS is working on the development of instruments for the detection and capture of invasive reptiles in Florida. (Credit: Reuters)

A group of South American lizards, known as tegu lizards, have taken over parts of Florida and there is concern that they would be able to expand in the southwest of the U.S. in what is described as an “invasion.”

The size of a small child, tegu lizards can grow to 4 metres in length. According to a study published in the scientific journal Nature, these lizards, which are native in South America east of the Andes, the capacity to take over “much of the southern United States and northern Mexico” if not kept in check.

“Our results suggest that a large part of the southern United States and northern Mexico, likely contains suitable habitat for one or more of the tegu species,” the study abstract reads.


There are two types of tegu lizards, with the established presence in Florida (Salvator merianae, the Argentine black and white tegu), and Tupinambis teguixin sensu lato (gold tegu), and a third party who has a presence here. They are brought to the U.S. as pets, and there is concern that if owners dump them in the wild, they can cause severe damage to the ecosystem.

“They are voracious, omnivorous, predatory animals that can live in a variety of habitats, but we can’t know what’s going to happen or how intense this invasion is going to be the effects on us,” Texas A&M professor Lee Fitzgerald told Reuters.

Mr. Fitzgerald is also co-author of the earlier study referred to above, together with a number of other researchers.

The omnivorous tegu lizards are known to eat alligator and bird eggs. They have also been spotted to consume things such as fruits, fungi, and small vertebrates. However, a 2002 study shows that the consumption of meat decreases as the animals grow older.

It is unclear how fruitful the tegu lizard population, but the Everglades Cooperative Invasive Species management area writes on her website that when people see them, they must have a photo, the location, and the report of the sighting by calling 1-888-IVE-GOT1 or online at


Their appeal as a pet can result from their unusually high intelligence. Some tegu lizards are known to look for human affection, similar to dogs and cats, and others can also be trained to come on command or house-broken.

The study added that it can take years for the pesky pests to reach their extended areas, causing concern for the animal owners and anyone who is dependent on the current ecosystem.

“We suggest that Florida is not the only country where these taxa may be adopted, and that early detection and rapid response programs aimed at tegu lizards in potentially suitable habitats elsewhere in North America, may help prevent establishment and reduce adverse effects on indigenous ecosystems,” the summary reads.

Follow Chris Ciaccia on Twitter @Chris_Ciaccia

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