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How pythons went from pets to pests

Alex Wolf guns a Jeep Liberty along a desolate two-lane road, swerving occasionally to dodge toads, night hawks and cottonmouth snakes. ¶ A full moon backlights the water-logged hammocks, and the orange glow of Miami is unmistakable to the northeast. Mosquitoes splat against the windshield and buzz around the floorboards.

This is how Wolf and fellow snake researcher Brian Greeves spend two nights a week: driving back and forth, over and over again, along the 50 miles of paved roads that cut through Everglades National Park at the southern tip of Florida.

They're hunting for Burmese pythons, the giant snakes from southeast Asia that are rapidly reproducing in the Everglades. The snakes have found their way into just about every corner of the 1.5-million-acre Everglades, where wildlife experts believe tens of thousands of them are slithering around. Some have even turned up in Key Largo with endangered woodrats in their bellies.

Despite all this, there is no formal plan to remove the pythons, which can lay up to 100 eggs and reach more than 20 feet in length.

"We're just trying to keep them from spreading northward," says Wolf.

If ever there was a way to underscore the difficulty of this, it would be to watch Wolf and Greeves at work on this warm summer evening trying to catch just one snake for their research.

They're waiting for a chance encounter.

They're waiting for a python to cross the road.

Some 400 species of exotic wildlife and fish have been documented in the wild in Florida, including 125 species that are established and breeding. As far back as 30 years ago, a Smithsonian publication described the state as a "biological cesspool of introduced life."

Nile monitor lizards have roamed Cape Coral since 1990. A population of caymans are breeding at Homestead Air Force Base. Boa constrictors have been reproducing in a natural park in southern Miami-Dade County for nearly 40 years. Iguanas from Central and South America devour impatiens, hibiscus and roses in gardens from West Palm Beach to Big Pine Key.

But no species is more worrisome and more damaging to the environment than the Burmese python.

"One of the things that sets the Burmese pythons apart and makes this threat so serious is that they're in ... the most remote, hardest-to-reach part of the Everglades," said Frank Mazzotti, a wildlife scientist at the University of Florida in Fort Lauderdale.

The extent of the problem has become clear only in the past few years. The first Burmese python was discovered inside the Everglades in 1979, but it wasn't until 2003 that scientists realized they had a serious problem. In May 2006, they found their first nest.

To date, more than 600 pythons have been removed from the Everglades, including 248 in 2007. Studies have shown them to be genetically similar, indicating that they are descendants of just a few pet pythons that were likely released.

Pythons reproduce easily. On rare occasions, they've been known to reproduce without a male, and females are also known to store male sperm. They produce large clutches of eggs, and the hatchlings tend to survive because they are so large.

How far Burmese pythons might spread has been debated widely in recent months. One U.S. Geological Survey study suggested they could survive in the lower third of the United States — as far north as Virginia and possibly even Illinois. But a team of wildlife niche experts from the City University of New York argued that Burmese pythons are unlikely to live north of Florida.

Both teams of researchers agreed the snake's range is likely somewhere in the middle, with most of Florida, particularly its coastlines, presenting optimal living arrangements for the giant snakes.

"I'm not making light of the problem in Florida," said Frank Burbrink, a professor of biology at City University of New York. "It just doesn't make sense for the rest of the U.S."

For now, Burmese pythons are known to be breeding only in the Everglades. But there is no doubt they are moving. On one 1,500-acre farm at the edge of the Everglades near Homestead, a farmer preparing his fields in 2005 found 22 of them, most of them chopped up by his plow. Two years later, there were 55.

Burmese pythons are also moving north to Alligator Alley and west toward the Big Cypress National Preserve and the Florida Panther National Wildlife Refuge in Collier County.

But pet Burmese pythons are also escaping or being released across the entire state. They've been found in Tampa, Cocoa Beach, Gainesville, Bradenton, Fort Myers, Marco Island, Vero Beach, Palm Beach Gardens, Port Richey, Panama City and Silver Springs, according to news reports.

In 2006, two Burmese pythons that were removed from the side of State Road 70 in Manatee County were caught in the act of breeding.

• • •

At a smelly lab inside Everglades National Park, wildlife biologist Skip Snow is performing a python necropsy. Red blood oozes from a gaping slit that runs the length of the 7-foot snake.

Inside, Snow squeezes out the contents of the snake's stomach. The results are tiny sausages that look like steel wool. For Snow, it is the key to what is really happening in the Everglades.

"I'll look at anything," says Snow, "anything I can get for this particular fight.''

As he pulls apart the balls, you realize they are congealed fur. He pulls out tiny teeth, whiskers, a small jaw.

"It looks like a small- to medium-size rodent, maybe a cotton rat," he says, documenting his find in a tiny yellow field journal, titled "Book No. 23, Big Snake Project."

Burmese pythons gobble up dozens of native species, from songbirds and white ibis to fawns and muskrats.

And they've tangled at least 10 times with alligators.

In one case, the foes fought for more than 24 hours before going their separate ways. In another, the snake ate the alligator, producing the well-known photo of the exploded snake with an alligator inside it. But most of the time the alligators win.

Still, the showdowns remind wildlife biologists of the environmental damage likely being wrought by the snake in the far reaches of the Everglades. No one has seen a muskrat lodge in a while. One python was spotted near several nesting egrets.

And they're eating endangered species. A wood stork was found in one snake's belly. Other pythons have devoured at least four woodrats from the Florida Keys, where only 200 remain in the wild in the world.

Snow, who has worked inside Everglades National Park for decades, has a tendency to look beyond the python. What if other species are released and become entrenched in the Everglades, too?

"We've got this giant roulette game going on," Snow said, "where no one is in control. Someone needs to get in control."

Snake enthusiasts think the wildlife biologists are exaggerating the problem, using scare tactics to try to ban the importation of exotic species into this country.

But Snow thinks the problem is so severe he would like to see certain exotic animals evaluated for their potential to damage the local environment — before they're imported into the country.

"The hobbyists think we're fabricating this to ban the import, but the truth is I'm scared to death about this," said Mazzotti. "These people just don't understand what's going on."

Sen. Bill Nelson, D-Fla., plans to introduce legislation next month that would ban the import of Burmese pythons into the United States. If it is enacted, Burmese pythons could no longer be sold across state lines.

• • •

Snake No. 15, a 10-foot male, is missing. So is No. 18, a female.

University of Florida researcher Mike Rochford is listening for their signals 2,000 feet over the Everglades in a small four-seater plane. Each snake has its own radio frequency, but neither is near its last known position.

Eighteen snakes have been surgically implanted with radio transmitters and returned to the Everglades in the past few years. Most have either died or been removed for one reason or another. Just four remain.

Once a week, Rochford, 27, flies overhead to document their progress for Mazzotti, the UF research professor who has a grant to track the snakes in the wild.

"I'm about out of ideas on that one," says Rochford, after the plane passes near Snake No. 15's last known position about half a dozen times.

Sometimes, he says, they disappear and turn up in the oddest of places. One snake moved 48 miles in a few months to return to the place where it was captured.

Still, the information gleaned from the radio telemetry project has been invaluable. One male snake led them to a group of eight snakes in a mating ball. Two got away; the other six were removed and killed.

One of the snakes they were tracking got pregnant herself. They could tell because she stopped moving and went underground. The clutch of 46 eggs was studied and destroyed. The snake was killed.

All told, several state and federal agencies are spending about $500,000 to study Burmese pythons and remove them.

Among the solutions: a trap that would catch pythons but not native animals. Several designs are being tested in the Everglades, but so far no pythons have been caught this way.

Mazzotti wants 10 more snakes fitted with radio transmitters so they can learn even more about the snakes.

But it comes down to this: Wolf and Greeves, Mazzotti's assistants, and two more researchers in another pickup truck spend more than four hours traveling the main road into Everglades National Park on a muggy night in mid August.

And they find just one snake crossing the road.

Times researcher Shirl Kennedy contributed to this report. Leonora LaPeter Anton can be reached at or (727) 893-8640.

By the numbers: Pythons in Florida

112,000: Number of Burmese pythons imported into the United States for the pet trade since 1990

$65-$80: Cost of a Burmese python in a pet store

16 feet and 152 pounds: Largest python found in the Everglades

418: Pythons captured and removed from Everglades National Park in 2006 and 2007

29: Number of species found in the stomachs of pythons removed from the Everglades.

0: Human deaths from pythons in the wild in Florida

$1,000 and up to 1 year in prison: Possible punishment for releasing exotic wildlife into the wild

How pythons went from pets to pests 08/23/08 [Last modified: Tuesday, August 26, 2008 6:20pm]
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