Georgia wildlife biologists felt a little thrill of fear when they saw a news item out of south Georgia last month.
Two men saw an 11-foot Burmese python slithering across a Charlton County back road, followed it into the woods and shot it.
The biologists weren’t worried about the unfortunate python’s fate, however.
Their fear was for the future of the Okefenokee Swamp, much of which is in Charlton, Georgia’s southernmost county. Burmese pythons, invasive natives of Asia, have already overrun the Everglades and Big Cypress swamps in south Florida, taking a drastic toll on the swamps’ mammal and bird life and altering the swamp’s ecology in ways that will play out for decades.
Breeding populations of the big snakes are also established in the Florida Panhandle and northern Florida — not so far from Georgia and the Okefenokee.
Had the pythons already reached the Okefenokee? Biologists thought it would be years, if ever, that they would reach Georgia —but scientists didn’t realize the secretive snakes were breeding in the Everglades until after they were well established, too numerous to escape attention any more.
The wildlife scientists believe the big snake in Charlton County was an aberration, however, not necessarily a sign of things to come.
“If they became established in Georgia, that could be a big problem, but I think it’s a little paranoid to worry about Georgia,” said John Jensen, a biologist with the state Department of Natural Resources’ Nongame Conservation Section.
After that first little tingle of fear, Jensen and other biologists concluded the Charlton County snake was likely a pet someone released, not part of an established population.
“That’s why a lot (pythons) show up where they do. People buy a three-foot snake and feed it a few rats, and all at once it’s a ten-foot snake,” said retired University of Georgia ecologist and Whit Gibbons.
Then they decide to release the snake, thinking maybe they’re doing the reptile a favor, he said.
The burgeoning Burmese python population may have begun with such pet releases; another factor was probably Hurricane Andrew, which destroyed a south Florida python breeding facility and damaged zoos and other places where wild animals were kept.
Gibbons and other UGA researchers brought some of the pythons a few years ago to the university’s Savannah River Ecology Laboratory, just across the state line in South Carolina. They wanted to see if the snakes could survive further north.
The snakes showed they could survive frosts,, said ecologist J.D. Willson, who worked with Gibbons on the Savannah River project. But a long cold spell in the winter of 2010 killed them all.
Even down in south Georgia’s Okefenokee, it’s too cold for the big snakes, natives of Asia which can reach 15 feet in length and swallow full-grown deer, the biologists suspect.
“I wouldn’t think they could make it through the winter,”, Gibbons said.
“I think they’ll get stopped at about Gainesville (Fla.), agreed Joe Butler, a biologist at the University of North Florida in Jacksonville.
Even southernmost Georgia gets too cold for the tropical pythons to survive, Gibbons said.
But not everyone agrees, noted Willson,, now a biology professor at the University of Arkansas. One controversial study concluded that pythons could survive as far northward as Washington, D.C.
“That question’s still very much open to debate,” he said. “We probably won’t really know how far they expand until it happens.”
If the big snakes do manage to establish themselves in the Okefenokee, the consequences for the swamp could be dire.
Willson has been studying the impact of the snakes in Everglades National Park and Big Cypress National Preserve, and what he’s seen is alarming.
In the south Florida swamps where the pythons have been established the longest, very few mammals like raccoons and deer remain, Willson said.
“I haven’t seen a rabbit in the Everglades in five years,” he said.
The snakes, which kill their prey by constriction — squeezing — may be a threat to endangered native species such as the Florida panther and American crocodile, not by directly attacking them but because the snakes are reducing the food supply for other predators like the crocodiles and panthers.
And with deer, raccoons and other native animals reduced, the Everglades themselves may change: animals shape plant evolution just as plants shape animal evolution.