Egg-eating lizards shaking up wildlife balance in S. Florida
The Argentine tegu lizard has invaded Florida and has the potential to cause even more ecological damage than the Burmese pythons that have drawn international attention in recent years. And now, scientists say, it’s too late to eradicate the tegus.
The Miami Herald
MIAMI — The Argentine tegu lizard doesn’t grow nearly as big as a Burmese python, but it may be a greater threat to South Florida’s native animals.
At a maximum size of 4 feet, a tegu can’t gobble down a full-grown deer or alligator with its rapier-sharp teeth. But the invasive, black and white reptiles have the potential to cause even more ecological damage than the 18-foot snakes that have drawn attention in recent years. And now, scientists say, it’s too late to eradicate them.
“When we first found out about them in 2008, we thought we had a chance to nip this population in the bud,” said the National Park Service’s Tony Pernas, who co-chairs the Everglades Cooperative Invasive Species Management Area group. “Now we’ve changed from eradication mode to containment mode.”
Long a staple of the exotic pet trade, the tegus likely were released by irresponsible owners or escaped from breeding facilities in south Miami-Dade County. Right now, the escapees’ epicenter is in the Florida City-Homestead area where federal, state and local agencies — with help from private trappers — are trying to round up as many as possible before the animals go into hibernation this fall. Another distinct population has cropped up in west-central Florida’s Polk-Hillsborough county area.
The chief worry among scientists and wildlife managers is the tegus fanning out to neighboring Everglades National Park (where a few have been captured) as well as east to Florida Power & Light’s Turkey Point nuclear-power plant and south to the Crocodile Lake National Wildlife Refuge in north Key Largo. Containment is urgent, they say, because the lizards will eat just about anything — small mammals, birds, insects, plants and their all-time favorite, eggs. That means goodbye to the baby American crocodiles that would have hatched in the refuge and the sand berms of the power plant — and recently were reclassified as a threatened rather than an endangered species. It could also mean lights out for the endangered Key Largo wood rat — not to mention other native creatures.
“They have the potential to impact all kinds of listed species,” said Jenny Eckles, nonnative wildlife biologist with the Florida Fish and Wildlife Conservation Commission (FWC). “Tegus can go through the water. They’re very adaptable to a number of different habitats, which is why we consider them to be problematic.”
Unlike Burmese pythons, whose numbers were knocked down by an extended cold period in early 2010, tegus thrive in temperatures as low as 35 degrees and as high as South Florida’s steamiest. Eckles and others tracking them say they often find tegus out in the open during the hottest time of day.
The animals hibernate in burrows from October until about January or February, then emerge to forage and reproduce. Females can lay 35 eggs a year.
Eckles and other scientists say they don’t know the size of the tegu population. But their numbers definitely are on the rise. Pernas said trappers caught 13 in 2009. This past summer, researchers from the FWC, National Park Service, ZooMiami, University of Florida, South Florida Water Management District and U.S. Geological Survey have captured more than 140 — mainly from public lands — which were euthanized humanely, according to Eckles. She said citizen trappers have taken more than 300 from private lands with permission from landowners. People do not need a special permit to trap and keep tegus, as they do with Burmese pythons. However, they must obtain a license to sell exotic wildlife.
Tegus are difficult to catch by hand and easier to trap using eggs as bait, according to Jake Edwards, a wildlife technician hired by FWC to capture the lizards in South Florida.
On a recent hike checking traps in the Southern Glades Wildlife and Environmental Area, Edwards tried unsuccessfully to catch a couple of free-roaming tegus.
But neither Edwards, nor Jeff Fobb — a trapper who also heads Miami-Dade Fire Rescue’s Venom One unit — recommends grabbing a tegu by hand, because of its damaging teeth and claws.
“I’d rather get bit by a 10-foot snake than that guy right there,” Fobb said, pointing to a 2-footer he recently caught in someone’s garage.