Burmese pythons are literally eating their way through the Everglades.
With no natural predators, these invasive reptiles – imported from Southeast Asia as pets – appear to be wiping out most of the small mammals that once thrived in Everglades National Park. They are also chasing out other predators, who have to go elsewhere for a steady diet of rodents, mink, rabbits and raccoons.
Scientists like Davidson College’s Michael Dorcas have shown that the populations of mammals including raccoons, possums and deer has dropped dramatically in the Everglades. They strongly suspected the fast-breeding snakes were to blame, but it took a study out this week in the journal Proceedings of the Royal Society to confirm the link.
In an ingenious experiment, scientists put radio collars on marsh rabbits and placed them in areas known to be favorite haunts of Burmese pythons.
Initially the rabbits thrived and even bred successfully. But after nine months, the researchers returned to find that pythons had eaten 77 percent of the rabbits. In control sites outside the park, pythons ate no rabbits.
“All of us were shocked by the results. Rabbit populations are supposed to be regulated by factors other than predation, like drought, disease,” study co-author Bob Reed, chief of the invasive branch of the United States Geological Society, told CBS News.
“They are so fecund. They are supposed to be hugely resilient to predation,” he said. “You don’t expect a population to be wiped out by predation.”
University of Florida’s Robert A. McCleery, another author on the paper, said the evidence against the python was pretty damning: The radio collars, along with the rabbits, were found in the snake’s belly.
“Every one (of the rabbits) we are saying was eaten by a python, we found inside a python,” he said. “It wasn’t like, ‘I wonder what ate this.’ You are looking for your rabbit and you find a python. The radio collar was transmitting from inside the python.”
Reed and the other authors said the findings raised the prospect that “pythons have replaced mammals” such as coyotes and bobcats “as the dominant predators on things like rabbits” in the Everglades.
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SOURCE: CBS News, Michael Casey