A genetic study has found that some specimens of the invasive reptile that has decimated local wildlife are a mixture of two Asian species which could make it an even more formidable predator
Florida: From carnivorous giant lizards to toxic climbing tree frogs, the Florida Everglades have become a haven to invasive species steadily destroying and devouring the flora and fauna of the state’s famed River of Grass.
Now comes news of a hybrid super-predator slithering its way through the waterways of the 1.5m-acre wilderness: a genetically blended python that researchers believe might be able to better embrace the subtropical environment and expand its range more rapidly than any species before it.
The discovery was made during a study to improve knowledge of non-native species. US Geological Survey (USGS) scientists analysed 400 snakes captured in the Everglades over a 10-year period from 2001.
The researchers expected to find only the pure genetic makeup of the Burmese python, the deadly constrictor that has exploded in numbers to supplant the American alligator as the region’s apex predator since a small number of unwanted pets were released in the 1980s.
Instead, they were surprised to uncover “a tangled family tree”, the genetic signature of the Indian rock python present in at least 13 snakes. That species is smaller, faster and arguably more aggressive than its big cousin, and thrives on higher and drier ground. Burmese pythons are more at home in the water.
“When two species come together they each have a unique set of genetic traits and characteristics they use to increase their survival and their unique habitats and environments,” said Margaret Hunter, a USGS research geneticist and the lead author of the report.
“You bring these different traits together and sometimes the best of those traits will be selected in the offspring. That allows for the best of both worlds in the Everglades, it helps them to adapt to this new ecosystem potentially more rapidly.”
Hunter stressed that the genetic markers – found only in the snakes’ mytochondrial DNA passed down through the maternal line – do not mean a new species of super-snake has suddenly been unleashed on the Everglades. The researchers believe cross-breeding occurred before the pythons secured their foothold in Florida.
“The ones that have this signature would have to be female and breeding to pass it on to their offspring,” she said.
Also unclear is the impact of so-called “hybrid vigour” on an individual snake.
“Morphologically, lots of times if you have a hybrid between two good species, the hybrid shares the traits of both [but] how that translates to behaviour I don’t know,” said Steve Johnson, associate professor of wildlife ecology at the University of Florida.
“It would depend on what genes, what molecular information is in a hybrid and how that information relates to their behavior.”
Hunter, though, still sees this as an unwelcome development that could hamper already unsuccessful efforts to reduce or eliminate up to 150,000 pythons that have decimated native species including bobcats, foxes, rabbits and raccoons from the Florida Keys to north of Lake Okeechobee.
“It can potentially lead to a better ability to adapt to environmental stressors and changes,” she said. “In an invasive population like Burmese pythons in south Florida this could result in a broader or more rapid distribution. With how rapidly they’ve [already] increased their population and expanded it appears they’re doing quite well.”
Wildlife officials admit they are fighting a losing battle. Failed initiatives have included training dogs to sniff out the snakes and releasing pythons with radio transmitters to lead hunters to females carrying up to 100 eggs at a time.
Probably the most audacious effort came last year when two renowned snake catchers from India’s mountain-dwelling Irula tribe chanted their way across the Everglades for two months . They bagged 33 pythons. But that figure, like the 1,000-plus snakes killed to date in civilian hunting programmes, is a drop in the ocean.
The Florida Fish and Wildlife Commission (FWC) has recorded more than 500 invasive or non-native species in the state, including tegu lizards from South America that eat rodents, Cuban tree frogs that prey on smaller species of amphibians and green iguanas that feast on native plants.