Be sure to check out Nature on PBS Sunday night -- according to an article in today's NYTimes, the episode will cover the spread of Burmese pythons in the Everglades and other parts of Florida (see map below). The pythons are, of course, an exotic, non-native species, now numbering in the tens of thousands, introduced from two apparent sources. The first is fickle owners who buy a cute baby snake, then release it into the wild when it becomes unmanageably large as an adult. The second is escape into the wild from zoos or from the warehouses of those who (often illegally) import exotic species for sale, usually when a structure is damaged during a hurricane. The trade in exotic animals, reptiles, fish, insects and birds is both lucrative and cruel -- sometimes as few as 25% of the original number of captured creatures survive transport, warehousing and sale. In my never-to-be-humble opinion, those rat bastards who traffic in exotic species should be fed to piranhas.
One of the largest snakes in the world, Burmese python adults can range in length from 12 to 26 feet, and be as thick as a telephone pole. They prey upon or compete with native species, many of them endangered. Prey ranges in size from rabbits to alligators. Pythons pose an increasing threat to humans as they spread to the environmental limits of their potential range (see map at bottom). This is not the snakes' fault, though they will ultimately be the ones who suffer the consequences. It is irresponsible humans who are the root of the problem.
The introduction of invasive species is nothing new -- witness the spread of organisms as diverse as the European starling, kudzu, the zebra mussell, and the Norway rat. The list is long. Many of those species are so successful that they take over the environmental niches of native species, or fill niches which were previously unoccupied, or introduce genetic pollution to native species. They may also carry non-native diseases which decimate native populations. In an era of global trade, it is easy enough for exotic species to hitchhike to far-flung places aboard ships and aircraft. Spreading them intentionally is an ecological tragedy, and unconscionable. And now we face the prospect of pythons in the semi-tropical U.S. To paraphrase the old TV commercial -- "It is 10:00. Do you know where your children and pets are?"