Bob Freer, who owns a wildlife sanctuary, searching for pythons in Everglades National Park in 2010. Their numbers appear to have diminished since a cold snap in the state last year.

MIAMI — To live in South Florida is to make peace with flying cockroach behemoths, brigades of lizards that dart across walls (bedroom and otherwise) and frogs the size of cannonballs that loiter on driveways.

But even in a state as hospitable as this one to scaly, slithering creatures, enough is enough. Florida has the highest number of nonnative amphibians and reptile species, according to a recent University of Florida study, and some of them are obliterating native Floridian creatures.

Florida’s Congressional delegation is now trying to yank the welcome mat from at least some of these “exotic” species, namely nine kinds of large constrictor snakes. Setting aside their quarrels, Democrats and Republicans have jointly written to President Obama to get his administration to ban the importation and interstate trade of these snakes, which include the Burmese python, the boa constrictor and the green anaconda.

A federal Fish and Wildlife Service rule that would list the snakes as an “injurious species” has lingered for three years and still requires the approval of the Office and Management and Budget.

The snakes, particularly the large and powerful Burmese python, have proliferated in the Everglades, a trend that began in the 1980s but worsened after Hurricane Andrew destroyed several reptile houses in 1992. There are thousands of them in South Florida, although precise numbers are elusive. Today, the snakes are often sold by pet stores or online. They typically make it into the wild when they escape their homes or when owners release them because they can no longer care for them.

“South Florida has been invaded by nonnative wildlife, which disturbs our fragile ecosystem and preys on native species,” saidthe Nov. 22 letter to Mr. Obama, whose signers include Representative Debbie Wasserman Schultz, a Democrat, and Representative Allen B. West, a Republican from a neighboring district, a pair who seldom agree on anything. “We are spending billions of dollars to restore the Everglades and if additional invasive snakes are allowed to establish themselves, the native wildlife will be decimated.”

Of the nine snakes on the list, Burmese pythons pose the largest threat, although Florida’s cold snap last year appeared to have diminished their numbers. Impressive because of their length — some here grow to 16 feet — Burmese pythons can eat all manner of small animals like birds, other snakes and rodents. In some cases, though, they overindulge.

In October, a work crew tending to plants in the area spotted a 16-foot Burmese python on a little island not too far from Everglades National Park. The python bulged cartoonishly in its middle. Turns out it had eaten a 76-pound female deer, which was discovered by biologists during a necropsy. (The python was killed, as regulations allow.)

In 2005, a python was found dead with a six-foot alligator jutting out of its mouth. More serious, a 2-year-old girl in Oxford was strangled in her bed in 2009 by a pet Burmese python after it got loose from its terrarium.

The snakes, which favor the warmth and humidity of South Florida, typically hide out in the brush. During mating season, which is occurring now, they often sun themselves on levies near canals.

“Until these animals are listed as injurious, they will continue to flow into the country unabated,” Senator Bill Nelson, a Florida Democrat who has led the effort, said in a separate letter to Mr. Obama. “As I have said for years, it is only a matter of time before a python in the Everglades eats an endangered Florida panther.”

The holdup with the rule appears to be mostly bureaucratic. But there is some concern that licensed Florida snake dealers would have to shut down their operations and, in desperation, would free more snakes.

Last year, Florida tightened the rules on six kinds of pythons and the Nile monitor lizard, making it against the law to buy them as pets. People who already owned them were allowed to keep them, with a permit. But only licensed reptile dealers, researchers and exhibitors can sell them out of state. The federal rule would ban the importation and interstate trade of these snakes altogether.

Florida wildlife officials have grown more adept at tracking and killing invaders in the past decade. The state now holds an amnesty day for pet owners who want to give up their snakes and giant lizards for adoption to other people or facilities that can care for them. There is a hot line to report sightings. And the Python Patrol, a team of snake-loving volunteers run by the Nature Conservancy, routinely scours the Everglades looking for pythons.

The weather, though, may turn out to be Florida’s strongest ally. The 2010 cold snap is believed to have killed off a number of the pythons, although no one knows how many. In 2009, 367 pythons were captured in the Everglades. This year, the total is 130.

The cold weather’s impact on their ability to reproduce is still unknown. Pythons can lay about 60 eggs at a time.

“It will take us another year to find that out,” said Scott Hardin, the exotic species coordinator for the Florida Fish and Wildlife Conservation Commission. “But it takes twice as long to find a python now as before 2010, an indication they got scarcer.”

(Source: www.nytimes.com )