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Florida Invader: Tegu Lizard1

Steve A. Johnson and Monica McGarrity 2

Figure 1. Black-and-white tegu (Tupinambis merianae), also known as the giant Argentine tegu.
Figure 1.  Black-and-white tegu (Tupinambis merianae), also known as the giant Argentine tegu.
Credit: Mauro Teixeiro, Jr., Universidade de São Paolo, Brazil

Report tegu lizard sightings immediately:

Call the Florida Fish and Wildlife Conservation Commission's invasive species hotline at 1-888-IveGot1 (1-888-483-4681) to report live tegus.

Also visit the EDDMapS site to report positive or suspected tegu sightings: https://www.eddmaps.org/florida/index.cfm. You will need to create an account (which only takes a few minutes) to make a report, and ideally please upload a digital image of the lizard with your report. If you prefer to submit reports from your smartphone, simply download the free IveGot1 application to your iPhone from the App Store. For android phones, the IveGot1 application can be found at the Google Play store.

The Argentine black-and-white or giant Argentine tegu (), native to South America, was brought to Florida for the pet trade and has become established in three areas of Florida: southern Miami-Dade County, southwest Charlotte County, and west-central Hillsborough County. Individual lizards belonging to this species and two other tegu species have also been captured across the Florida peninsula, with several credible records also from the Panhandle. These large lizards grow to 4–5 feet long. Argentine black-and-white tegus eat native reptiles and their eggs, and likely also consume the eggs and young of ground-nesting birds. Tegus could negatively impact threatened and endangered species, including gopher tortoises. Tegus have been observed eating alligator eggs and could be a problem for threatened American crocodiles in southern Florida. They are opportunistic predators and consume a variety of small prey as well as plant matter and carrion (dead animals). In west-central Florida, black-and-white tegus inhabit dry, upland areas with sandy soils, including natural, urbanized, and agricultural areas. In southern Florida, they occur in densely vegetated areas along canals and roadsides. Tegus could potentially become an agricultural pest or a source of bacterial contamination of food crops. These lizards may dig their own burrows but also invade the burrows of native species, such as gopher tortoises. Tegus remain underground during late fall and winter months, even in southern Florida. Female Argentine black-and-white tegus in south Florida lay approximately 30 eggs per clutch in the spring and summer. They may live 15–20 years

Figure 2. The head and neck of a tegu are much thicker than those of a Nile monitor. The fleshy, forked tongue is red. In young animals, the head is greenish (as shown here).
Figure 2.  The head and neck of a tegu are much thicker than those of a Nile monitor. The fleshy, forked tongue is red. In young animals, the head is greenish (as shown here).
Credit: Dustin Smith, Zoo Miami

Figure 3. The body of black-and-white tegus is grayish and marked with dark bands with abundant light spots in between. Other tegu species are similarly marked, but base coloration may vary (as shown in Figure 4).
Figure 3.  The body of black-and-white tegus is grayish and marked with dark bands with abundant light spots in between. Other tegu species are similarly marked, but base coloration may vary (as shown in Figure 4).
Credit: Mario Sacramento, Universidade de Alfenas, Brazil

Figure 4. Several tegu species have been found in Florida, including the red tegu (shown here) and the gold tegu, which has a yellow-tan base color.
Figure 4.  Several tegu species have been found in Florida, including the red tegu (shown here) and the gold tegu, which has a yellow-tan base color.
Credit: Patrick Lynch, South Florida Water Management District (2009)

Identification

Learn more about Argentine black and white tegus, including what to do with a pet tegu you are no longer able to care for, at this site: https://myfwc.com/wildlifehabitats/profiles/reptiles/argentine-black-and-white-tegu/

Acknowledgments

This project was made possible in part by a grant from the South Florida National Parks Trust and the Ferris Greeney Family Foundation, and by the USDA-RREA. This document was created as additional reference material for the Introduced Reptile Early Detection and Documentation training program, also known as REDDy, which has since been retired and is no longer available.

Footnotes

1. This document is WEC295, one of a series of the Department of Wildlife Ecology and Conservation, UF/IFAS Extension. Original publication date August 2010. Revised February 2014, June 2017, and December 2020. Visit the EDIS website at https://edis.ifas.ufl.edu for the currently supported version of this publication.
2. Steve A. Johnson, associate professor and Extension specialist; and Monica McGarrity, Extension program assistant; Department of Wildlife Ecology and Conservation, UF/IFAS Extension, Gainesville, FL 32611.