Pythons wiping out mammals in Everglades, researchers say
A Burmese python in the Everglades swallowed a 76-pound deer last year.
January 31st, 2012
09:34 AM ET

Pythons wiping out mammals in Everglades, researchers say

Burmese pythons have eaten so many small mammals in Everglades National Park that populations of rabbits and foxes have disappeared and numbers of raccoons, opossums and bobcats have dropped as much as 99%, according to a report released Tuesday by researchers at Virginia Tech University, Davidson College and the U.S. Geological Survey.

“Pythons are wreaking havoc on one of America’s most beautiful, treasured, and naturally bountiful ecosystems,” said U.S. Geological Survey Director Marci McNutt in a statement.

The massive nonnative snakes have become an established species in the park in the past 11 years, after snakes that were once pets were released into the wild, according to the researchers. Park spokeswoman Linda Friar said earlier this month that there are tens of thousands of the snakes in the park.

In the remote southernmost regions of the 1.5 million-acre national park, researchers could find no marsh or cottontail rabbits or foxes. In those same areas, the raccoon population has declined 99.3%, the opossum population 98.9%, and the bobcat population 87.5%, the researchers reported.

Those animals are often found in the stomachs of Burmese pythons captured in the Everglades, the researchers said.

“The magnitude of these declines underscores the apparent incredible density of pythons in Everglades National Park,” said lead author Michael Dorcas, a biology professor at Davidson College in North Carolina.

To measure the population declines, researchers traveled more than 39,000 miles at night along roads in the park between 2003 and 2011, counting both live animals and road kills. Their data were compared to similar counts made along the same roads in 1996 and 1997, before the Burmese pythons had become an established species in the park.

In northern areas of the park, where python populations have not become established, the researchers found similar mammal numbers between their recent and older surveys. But in the area where the pythons have recently become established, the researches reported a noticeable decline in mammal numbers. They called for action before the pythons wipe out mammals in the entire park.

“Right now, the only hope to halt further python invasion into new areas is swift, decisive, and deliberate human action,” McNutt said.

Burmese pythons are native to southeast Asia, their range extending from southern China to the Malay Archipelago, according to the National Zoo. The snakes reach breeding age in four to five years and a female lays an average of 35 eggs during the spring breeding season, though one snake may lay up to 100. Burmese pythons can live as long as 30 years.

In their native range, the snakes are considered threatened and are hunted by humans for their meat and skins, according to the National Zoo.

They may grow up to 22 feet long but average about 16 feet. The snakes can swallow whole animals four or five times the size of their head. In the Everglades, the pythons have been found to eat deer and even alligators.

While the researchers are concerned about the fate of the raccoons and the opossums, they say they may not even be able to measure the snakes' effect on more elusive species.

“Such severe declines in easily seen mammals bode poorly for the many species of conservation concern that are more difficult to sample but that may also be vulnerable to python predation,” Dorcas said in a statement.

The researchers compared the proliferation of pythons in Florida to that of the brown tree snake on the Pacific island of Guam, where native species have disappeared since the introduction of the snakes. But they said it's happening faster in Florida.

“It took 30 years for the brown tree snake to be implicated in the nearly complete disappearance of mammals and birds on Guam; it has apparently taken only 11 years since pythons were recognized as being established in the Everglades for researchers to implicate pythons in the same kind of severe mammal declines,” U.S. Geological Survey scientist Robert Reed said in the report.

Earlier this month, the U.S. Fish and Wildlife Service instituted a ban on the importation of the Burmese python and three other nonnative constrictor snakes – the yellow anaconda and northern and southern African pythons.

But the researchers say they'll still need to do more.

“This severe decline in mammals is of significant concern to the overall health of the park’s large and complex ecosystem,” Everglades National Park Superintendent Dan Kimball said in a statement. “We will continue to enhance our efforts to control and manage the non-native python and to better understand the impacts on the park.”

The latest research was published this week in the Proceedings of the National Academy of Sciences.

Other stories you might be interested in:

Hunting snakes in Florida

Tylenol-spiked mice air-dropped to kill snakes

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Filed under: Animals • Florida • Snakes
soundoff (456 Responses)
  1. Big Deal

    95% of the honey bees in Arizona are now Africanized hybrids. 65% in southern California. NonNatives have crossed the sprecies barrrier.

    January 31, 2012 at 9:41 am | Report abuse | Reply
  2. ~Dep. Hector Rodrigo Martinez, US Border Patrol

    This is all very interesting.

    January 31, 2012 at 9:49 am | Report abuse | Reply
  3. banasy ©

    This is what happens when an animal that is not indigenous to a country is introduced into nature.

    January 31, 2012 at 10:02 am | Report abuse | Reply
    • concerned citizen

      europeans were not native to Americas!!!!

      January 31, 2012 at 10:22 am | Report abuse |
  4. Portland tony

    They've banned the import of the Burmese Python. Terrible news for importers, good news for domestic snake merchants though!

    January 31, 2012 at 10:03 am | Report abuse | Reply
  5. african rover

    Just get some scientists to confirm that to eat them is a powerful aphrodisiac, and then sell hunting licenses to Chinese tourists. They will be gone in 2 or 3 years.

    January 31, 2012 at 10:07 am | Report abuse | Reply
  6. S

    Or maybe just yours. Probably an even better thing.

    January 31, 2012 at 10:07 am | Report abuse | Reply
  7. Steve

    Grant work visa's for the hunters in Asia and let them take care of them. From reading above it would seem that they have taken care of them in Asia.

    January 31, 2012 at 10:08 am | Report abuse | Reply
    • Darrel

      Don't need to import hunters, put a 10 dollar a head bounty on them an in a year or two they'll be gone. there are plenty of hunters in this country.

      January 31, 2012 at 3:44 pm | Report abuse |
  8. uhhhh duh

    I wonder how many times this story will be re-written and posted on CNN..?? this is really OLD news.. thank you CNN for continuing to remove my post.

    January 31, 2012 at 10:09 am | Report abuse | Reply
    • ugh

      The presence of the pythons is old news. This article is reporting on the fact that researchers have confirmed that it's destroying its ecosystem, not simply competing with other predators. That is being released today.

      January 31, 2012 at 10:26 am | Report abuse |
  9. Chuck

    Lovely! Another problem completely and totally created by mankind.

    January 31, 2012 at 10:09 am | Report abuse | Reply
  10. Opportunity

    These snakes are valuable – for skin and meat. Someone should take advantage of the situation and profit.

    January 31, 2012 at 10:10 am | Report abuse | Reply
  11. Brownstain

    Global swarming

    January 31, 2012 at 10:11 am | Report abuse | Reply
    • doc

      Yes...and again caused my humans.

      January 31, 2012 at 10:17 am | Report abuse |
  12. Jack

    The US Fish and Wildlife could open a hunting season and even offer a bounty to kill these snakes. Say, five dollars a piece would make it worth while to hunt them down. Just a thought...

    January 31, 2012 at 10:13 am | Report abuse | Reply
    • JB

      LOL, The everglades is a little bit more rugged that the happy little highway that runs through it.

      January 31, 2012 at 1:35 pm | Report abuse |
  13. Jerry

    Mandate mfrs of snakeskin shoes and purses open businesses in the Everglades. Four problems solved at once (jobs, healthcare, taxes, and retirement funding).

    January 31, 2012 at 10:15 am | Report abuse | Reply
  14. doc

    With a name like Penis Wrangler, if they turn to hom~s, you'll be next.

    January 31, 2012 at 10:16 am | Report abuse | Reply
  15. Where do I get one?

    We could use a few of these in Colorado.......plenty of rabbits that need to be thinned.

    January 31, 2012 at 10:16 am | Report abuse | Reply
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