From the South Florida Sun-Sentinel
Native lizards being devoured by little 'T-Rex ' throughout South Florida
By David Fleshler | South Florida Sun-Sentinel
Posted May 1, 2006
With a ferocious little predator called the northern curlytail lizard, South Florida may finally have the exotic reptile it deserves.
Native to rocky areas of the Bahamas and nearby islands, the lizard has made a home in sections of southeast Florida that mimic its native habitat, such as sidewalks, parking lots and strip malls. As it spread through coastal areas of Broward and Palm Beach counties, it has crowded out native lizards and devoured the prey of native mockingbirds, grackles and shrikes.
"They're the T-Rex of our little ground critters," said Hank Smith, wildlife biologist for the Florida Park Service and affiliate research assistant professor at Florida Atlantic University's Wilkes Honors College in Jupiter. "They're larger than our native lizards that occur along the coastline: the green anole, the green racerunner. Wherever I find it, I find no other lizards."
Exotic, or nonnative, species are a growing environmental threat in an age of international trade, unusual pets and routine air travel. Brought to areas where they may have no natural enemies, they can out-compete and overwhelm native plants and animals, eliminating species that make an ecosystem unique.
In the past few years, attention has focused on Burmese pythons in the Everglades, a particularly frightening exotic species in a world-famous wilderness. But many other nonnative species have established themselves in South Florida, which lacks the periods of cold weather that tend to wipe out invaders elsewhere in the United States.
The lizard landed first in the town of Palm Beach in 1943, where a man imported 40 of them to eat the bugs on his sugar cane plants. They crossed the Flagler Bridge in 1968 and began colonizing the mainland.
Today they occupy an almost continuous range in urban areas from Lighthouse Point to Hobe Sound, with patches of habitat elsewhere. Earlier this year, biologists discovered about 50 of them living around a restaurant and motel on Lower Matecumbe Key, its southernmost outpost.
The lizards show themselves on sunny days, when they can be seen basking on sidewalks, ledges and other areas exposed to the sun. To absorb more sunlight, they uncurl their tails. Scientists are trying to learn more about the lizard's reproductive and eating habits, with the help of students from FAU and Palm Beach Community College. In keeping with the lizard's urban orientation, people studying them used parked cars as blinds.
Because it lives mainly in urban areas, the northern curlytail hasn't caught the attention of many environmental officials in Florida. A recent survey found they worried most about Burmese pythons, boa constrictors, brown anoles, green iguanas and Nile monitors, said Art Roybal, a biologist with the U.S. Fish and Wildlife Survey who coordinates the Florida Invasive Animal Task Team.
Roybal said the reason the northern curlytail may not have made the list is the team was focused on animals in the Everglades, which is not its habitat.
In urban areas, however, scientists say the northern curlytail could decimate populations of native lizards. Sitting in wait for grasshoppers, beetles and smaller lizards, the curlytail rushes its prey, killing and devouring it. Biologists have seen them rush and kill prey being stalked by native lizards. They say it could pose a threat to green anoles, six-lined racerunners, southeastern five-lined skinks and Florida scrub lizards.
"A curlytail shows up in downtown West Palm Beach, and it starts shoveling down brown anoles and anything else that moves," said Walter Meshaka, senior curator of the State Museum of Pennsylvania and the author of books and articles on Florida's reptiles and amphibians. "They're ferocious little carnivores. They'll eat anything. They grow quickly. They mature early. They do well around humans."
Now that there are thousands of these lizards in South Florida, there may be no way to get rid of them. But scientists and public officials are discussing ways to make it more difficult for such creatures to be released. The state Legislature is considering a bill that would require permits for owning certain nonnative reptiles and increase the penalties for releasing them.
Because some of the lizards are thought to be released pets, scientists are discussing the need to curtail the exotic pet trade. Roybal's invasive-animals team is working on policy recommendations, and restricting imports may be one of them, he said.
"There needs to be a hard look at what animals are brought into the U.S.," he said.
David Fleshler can be reached at
dfleshler@sun-sentinel.com or 954-356-4535.
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