MIAMI – Federal wildlife officials alarmed by an infestation of Burmese pythons in the Florida Everglades have tried radio tracking collars, a massive public hunt and even snake-sniffing dogs to control the invasive species. Now there's talk of snaring the elusive pythons in specially designed traps.
The U.S. Department of Agriculture received a patent in August for a trap that resembles a long, thin cage with a net at one end for the live capture of large, heavy snakes.
Researchers say Burmese pythons regard the Everglades as an all-you-can-eat buffet, where native mammals are easy prey and the snakes have no natural predators. The population of Burmese pythons, which are native to India and other parts of Asia, likely developed from pets released into the wild, either intentionally or in the aftermath of Hurricane Andrew in 1992.
Wildlife officials are racing to control the python population before it undermines ongoing efforts to restore natural water flow through the Everglades. According to a study released last year, mammal sightings in the Everglades are down sharply in areas where pythons are known to live.
The Gainesville field station for the National Wildlife Research Center, which falls under the USDA, is preparing to test the trap in a natural enclosure that contains five pythons.
Over the coming months, the researchers will try baiting the traps with the scent of small mammals such as rats, and they will try camouflaging them as pipes or other small, covered spaces where pythons like to hide, said John Humphrey, a biologist at the research center. Future tests may use python pheromones as bait.
"There's still more to be learned, there's still more to be tested," Humphrey said. "This is just one of your tools that you have to put together with other things to get the problem solved."
The trap was developed to catch exotic snakes without ensnaring smaller, lighter native species, Humphrey said.
The 5-foot-long trap is made from galvanized steel wire with a tightly woven net secured to one end. Two separate triggers need to be tripped simultaneously for it to close, which should keep it from snapping shut on such native snakes as the eastern diamondback rattlesnake or the water moccasin.
"The largest native snakes are generally somewhat smaller than the youngest of the pythons," Humphrey said. "That was the impetus of the design."
The longest python ever caught in Florida was an 18-foot-8-inch specimen found in May beside a rural Miami-Dade County road.
Humphrey developed the trap in collaboration with Wisconsin-based Tomahawk Live Trap, which is working on a licensing agreement to sell the traps along with other snake-handling equipment such as tongs, hooks and secure bags.
"We don't expect to sell a lot of them; it's not an everybody thing, not like a chipmunk or a squirrel trap," said co-owner Jenny Smith. But she said it has potential for wildlife removal companies when they get calls about "a big snake."
It's not clear where exactly the traps would be deployed, or whether they would be effective in an area as vast as Florida's Everglades.
Everglades National Park alone encompasses 1.5 million acres, and all but roughly a hundred thousand acres of that is largely inaccessible swampland and sawgrass, vital breeding grounds for a variety of protected species.
It might not make sense, or even be possible, to place and monitor traps in hard-to-reach swamplands, said park spokeswoman Linda Friar.
Traps have been used in the park to collect pythons for research but not for population control, Friar said.
Most of the state and federal efforts aimed at pythons have focused on learning how the elusive snakes have adapted so well in the wild, and that learning process continues, she said.
"They're so difficult to track and find," Friar said. "What we do know is they've adapted. We don't know how many there are."
One of the challenges facing wildlife officials is that the tan, splotchy snakes are incredibly difficult to spot in the wild, even for seasoned hunters. Researchers say they'll fail to see a python they're tracking with a radio collar until they're practically standing on it.
The Florida Fish and Wildlife Conservation Commission allows hunters with special permits to remove pythons and other exotic reptiles from some state lands. Earlier this year, a state-sanctioned hunt that attracted worldwide media attention. Roughly 1,600 amateur python hunters joined the permit holders for a month, netting a total of 68 snakes.
In an Auburn University experiment, specially trained dogs found more pythons than their human counterparts, but researchers also found that the dogs, much like humans, would falter the longer they worked in South Florida's often oppressive humidity.
State wildlife officials also try to catch pythons through "exotic pet amnesty days" where people can relinquish non-native species with no questions asked. They also urge residents to report encounters with pythons and other invasive species to a hotline, www.IVEGOT1.org. Florida prohibits the possession or sale of pythons for use as pets, and federal law bans the importation and interstate sale of the species.
A prolonged cold snap has proven to be one of the better methods of python population control, killing off large numbers of the snakes in 2010. The population rebounded, though, because low temperatures aren't reliable in subtropical South Florida and because pythons reproduce quickly and in large numbers.
Other traps set for pythons in the past haven't been effective, but traps have been successfully used to capture other exotic species such as black-and-white tegu lizards, said conservation commission spokeswoman Carli Segelson.
"It may be something that if it doesn't work for the python, it may work for other species," she said.