The Argentine black and white tegu (Salvator merianae) has become an invasive species in Florida. This large reptile, not native to North America, has established breeding populations across the state. Its emergence highlights the complex challenges posed by non-native animals introduced into new environments. Understanding how the tegu arrived in Florida is essential to comprehending its ecological impact.
The Tegu Lizard
The Argentine black and white tegu is a substantial lizard, capable of reaching lengths up to 4.5 feet and weighing around 10 pounds. Its distinctive appearance features a mottled black and white coloration, often arranged in a banded pattern. Hatchlings exhibit bright green heads that fade with age, while adult tegus possess strong jaws and sharp teeth.
Native to South America, including regions of Brazil, Paraguay, Uruguay, and Argentina, tegus are highly adaptable omnivores. Their diet consists of fruits, insects, eggs, small mammals, and other reptiles. They are terrestrial burrowing lizards that can also swim effectively and tolerate varied habitats.
Arrival in Florida
The tegu lizard’s introduction to Florida primarily occurred through the exotic pet trade. Tegus became popular pets, but their substantial size and powerful bite made them challenging to manage as they matured. This often led to owners releasing them into the wild or the lizards escaping from outdoor enclosures.
Tegus began appearing in Florida around the early 2000s, with a self-sustaining wild population identified in Miami-Dade County by 2008. While isolated sightings of red and gold tegus have occurred, the Argentine black and white tegu is the species with established breeding populations.
Population Growth and Range Expansion
Once introduced, tegu populations grew rapidly across Florida. The state’s warm, subtropical climate closely mimics their native South American habitat, providing ideal conditions for survival and reproduction. Abundant food sources, including native wildlife and vegetation, further supported their proliferation.
Tegus also benefit from a lack of natural predators in Florida’s ecosystems, allowing them to thrive largely unchecked. Their high reproductive rate contributes significantly to population growth, with females laying an average of 35 eggs annually. Established breeding populations are now found in Miami-Dade, Hillsborough, Charlotte, and St. Lucie counties, with reports from at least 35 Florida counties.
Environmental Consequences
Tegu lizards have significant ecological impacts in Florida, primarily due to their omnivorous diet and opportunistic feeding habits. They are known predators of the nests of native ground-nesting birds and reptiles, consuming eggs of American alligators, American crocodiles, and various turtle species, including sea turtles.
Tegus also prey upon threatened juvenile gopher tortoises. Their broad diet includes frogs, toads, other lizards, snakes, and small mammals. This predation disrupts Florida’s delicate ecological balance and competes with native species for essential food resources.
Controlling the Invasion
Florida state agencies and conservation groups have implemented various strategies to manage tegu populations. Trapping programs are a primary method of removal, with thousands of tegus removed by the Florida Fish and Wildlife Conservation Commission (FWC) and its partners.
Public reporting initiatives, such as the FWC’s Exotic Species Hotline and the IveGot1 application, encourage residents to report sightings, aiding in rapid response and containment. In April 2021, tegus were added to Florida’s Prohibited species list, banning their sale, breeding, and acquisition as pets. Existing pet owners could obtain a permit to keep their animals. These regulations aim to prevent further introductions and reduce the overall threat posed by this invasive species.