Tracking The Tegu: Tampa Bay's Everglades Connection

Michelle McEachern has always loved science. After high school in California, she moved to Tampa Bay to study marine biology at Eckerd College, a liberal arts college with a national reputation for that field of study.

She graduated from Eckerd in 2010 with a double major in marine science and environmental studies and now lives in South Florida where she works for the U.S. Geological Survey (USGS). She's part of a team of scientists tracking giant tegu lizards and Burmese pythons, two alien invaders that are threatening the balance in the Florida Keys and the Everglades.
 
Pythons have been considered a dangerous nonnative invader there for several decades.They also continually cause sensational headlines due to their enormous size -- a 17.5-foot, 164-pound female was caught in April of this year, the largest ever found in the Everglades. The tegu is relative newcomer, but of equal concern.

Originally from South America, tegus have unusual black-and-white markings on their leathery skin and are trendy in the exotic pet trade. They're big -- about four to five feet long, and they grow rapidly, getting up to 15 pounds. 
 
They were first spotted in Hillsborough County about five years ago. Now they're moving into South Florida and rapidly expanding their numbers.
 
"The USGS stand is that they've made their way into the Florida landscape through the pet trade -- whether owners intentionally released them or the animals simply escaped is unclear, but now it's a big problem,'' says McEachern.
 
While there haven't been reports of tegus harming people, there is major concern about their impact on the landscape, and on native mammals and birds.
 
Tegus are omnivorous, which means they eat plants, fruit, insects, small animals and eggs.

"They really like the eggs of ground nesting birds and reptiles,'' says McEachern. "There is concern about what they might do to birds and small mammals, as well as the potential to outcompete the large native predators like the alligator and the American crocodile, which is endangered.''
 
McEachern's day-to-day tasks include checking traps that USGS scientists have placed in the Florida Keys for the reptiles. Once caught, the animals are handed over either to scientists at the University of Florida or Everglades National Park for further study. The 17.5-foot python caught in April was euthanized and dissected by UF scientists, who found the snake was a pregnant female with 87 eggs.

Transmitting For Science
 
McEachern and her team members also conduct radio telemetry surveillance of both pythons and tegus. She outfits the tegus with transmitters, which she jokingly calls "backpacks.'' The backpacks are secured on the reptile with a small beaded chain placed around the pelvic area, she says. It's definitely a job that requires special care and attention.

"We hold the tegu just behind the head so the animal can't swing around and bite us,'' says McEachern. "We also have to hold the back legs down -- they have long claws that are very sharp so you have to be very careful.''
 
The transmitters allow the scientists to monitor the lizards' habitat, range, population size, route, what they're eating and other data. 

"The whole point is to learn as much as we can so we can figure out how to control and contain them,'' says McEachern. "The ultimate goal is to remove nonnative species completely from the landscape. Our research will help figure how that is best accomplished with the least impact on the environment.''
 
Cuts to funding will cause McEachern's project to end later this year. But USGS will continue to have a presence in the areas, as will other scientific organizations, including UF and the Florida Fish and Wildlife Conservation Commission.
 
As for McEachern, she plans to go to graduate school to continue her scientific studies, perhaps in marine conservation biology. "If you're a curious person and you want to know about the world around you, science is the place for you,'' she says.

Janan Talafer is a freelance writer in St. Petersburg, FL, who shares a home office with her dog Bear and two cats Milo and Nigel. Comments? Contact 83 Degrees.