Tegu lizards, which are known for their large stature and predatory habits, have been multiplying in population in South Florida ever since the first one was spotted in 2008 near a Homestead trailer park in the southern part of Miami-Dade County.
Some have since established a foothold off the 18-Mile Stretch and are believed to have made forays into the Florida Keys.
“Their threat potential is serious,” University of Florida biologist Frank Mazzotti told the Free Press. “It’s hard to accurately measure their numbers, but the extent of their population is definitely growing rapidly.”
Mazzotti, along with a team of researchers, has been trapping tegus since 2010. More recently, he was contracted as part of a South Florida Water Management District and Florida Fish and Wildlife Conservation Commission trap-kill-study program.
The program, in place for the last three years, serves two purposes, Mazzotti said. It helps eradicate the tegus while allowing their behavior to be studied.
Tegus, which belong to the Teiidae family, average around 3 feet in length and are native to Central and South Americas. How the first one ended up in South Florida, though, is not entirely clear, although many researchers believe it was either an escaped or freed pet.
Mazzotti said the non-natives have been found all the way north to the Florida panhandle, mainly because of their adaptation to colder climates. Pythons, on the other hand, have not strayed too far from South Florida’s steamy environs.
“We do not know their exact boundaries,” Mazzotti said of the tegus. “So it’s difficult to measure their full impact.”
Tegus, as well, are still readily available for purchase in many pet stores.
An area along a jarring dirt road in the Southern Everglades, not far from the Dade Juvenile Residential Center located off the 18-Mile Stretch, seems to be the prime real estate for the majority of the tegu population, according to researchers.
This, in turn, means much of the wildlife native to South Florida has the potential to fall victim to the omnivorous tegus.
“They eat everything, including small animals,” Mazzotti said. “I’d hate to be a Key Largo woodrat or a Lower Keys marsh rabbit.”
Tegus have also been caught feasting on alligator eggs on multiple occasions, he said. Another potential victim, considering around 30 to 40 percent of the invasive species diet is made up of small animals, is the endangered Cape Sable seaside sparrow.
“The frequency of small animals they prey on is just astonishing,” Mazzotti said.
A U.S. Geological Survey study published earlier this year focused on the relationship between tegus and altered habitats in the Everglades area. It found that the lizards prefer the outer reaches of the Everglades, near drained wetlands and roads, over the dense center. Florida, researchers said, is home to more invasive species than other states, in part, because of its wetlands and forests.
Why should South Florida even worry about the rapid growth of non-natives such as tegus and pythons?
“Both are very serious threats [to the Everglades ecosystem]. And we’re spending billions of dollars to restore the Everglades,” Mazzotti said. “Are we just going to let invasive species take it over?”