Massive, voracious lizards are invading the southwestern US

A group of South American lizards, known as tegu lizards, have taken over parts of Florida and there is concern they could expand into the southwestern U.S. in what is being described as an "invasion."

The size of a small child, tegu lizards can grow up to 4 feet in length. According to a study published in the scientific journal Nature, these lizards, which are indigenous to South America east of the Andes, have the capacity to take over "much of the southern United States and northern México" if not kept in check.

"Our results suggest that much of the southern United States and northern Mexico probably contains suitable habitat for one or more of these tegu species," the study's abstract reads.


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

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

Fitzgerald is also a co-author of the aforementioned study, along with several other researchers.

The omnivorous tegu lizards have been known to eat alligator and bird eggs. They have also been spotted consuming things like fruit, fungi and small vertebrates. However, a 2002 study shows that meat consumption decreases as the animals age.

It's unclear how prolific the tegu lizard population has become, but the Everglades Cooperative Invasive Species Management Area writes on its website that if people see them, they should take a picture, note the location and report the sighting by calling 1-888-IVE-GOT1 or going online at


Their appeal as pets may stem from their unusually high intelligence. Some tegu lizards have been known to look for human affection, similar to dogs and cats and others can even be trained to come on command or be house-broken.

The study added that it could take years for the pesky pests to reach their expanded areas, causing concern for wildlife owners and anyone else that depends on the current ecosystem.

"We propose that Florida is not the only state where these taxa could become established, and that early detection and rapid response programs targeting tegu lizards in potentially suitable habitat elsewhere in North America could help prevent establishment and abate negative impacts on native ecosystems," the abstract reads.

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