This article fits the thread so well I posted it. I saw a TV special on this recently, Fox I think. Some of you may have also. The state of Florida is contemplating putting a bounty on these Burmese pythons, said the program.
Huge, Freed Pet Pythons Invade Florida Everglades
"...For now, the alligators in the Florida Everglades are holding their ground against the invading snakes. But the odds may be changing. The park is being overrun with Burmese pythons, one of the world's largest snakes. These pythons can grow to be more than 20 feet (6 meters) long in their natural habitat in Southeast Asia.
The Burmese python is just one of thousands of non-native animal and plant species that have invaded the United States in the last decades. Florida teems with exotic creatures that have no business living there. Other regions have their own problems. Snakehead fish, for example, have infested the Potomac River near Washington, D.C.
The economic toll from damage by invasive species—and the costs of trying to control them—is enormous: U.S. $137 billion a year, according to a 1999 Cornell University study..."
Huge, Freed Pet Pythons Invade Florida Everglades
(National Geographic write-up)