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.

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

    I don't understand the issue. If they're nonnative and wreaking havoc on that which is, exterminate them.

    January 31, 2012 at 4:57 pm | Report abuse |
  2. Jeff

    Down 99% Sorry, I'm not buying that number. Sounds over inflated to get action taken. I'm not saying nothing needs to be done, but 99% decline in several species. Come on.....

    January 31, 2012 at 4:58 pm | Report abuse |
  3. Kill them all

    Let God sort them out.

    January 31, 2012 at 5:00 pm | Report abuse |
    • JT

      Better yet, we need to put you out.

      January 31, 2012 at 6:24 pm | Report abuse |
  4. Mike

    Put a good bounty on the snakes~!

    January 31, 2012 at 5:10 pm | Report abuse |
  5. Bill

    Snakeskin boots for all!

    January 31, 2012 at 5:18 pm | Report abuse |
  6. Debbie


    January 31, 2012 at 5:26 pm | Report abuse |
    • Pulsedpower

      I had one for years. Her name was Debbie. Wonder which one of you is uglier?
      P.S. There's a button on the left of the keyboard labeled "Caps Lock" please turn it off.

      January 31, 2012 at 6:30 pm | Report abuse |
  7. Intelligent Republican

    This is obviously Obama's fault!

    January 31, 2012 at 5:38 pm | Report abuse |
  8. cpc65

    Crossbreed mongooses with grizzly bears and turn them loose!

    January 31, 2012 at 5:45 pm | Report abuse |
    • ksc74

      that would be awesome...

      January 31, 2012 at 7:04 pm | Report abuse |
  9. Atom

    Can I adopt a Floridian python?

    January 31, 2012 at 5:45 pm | Report abuse |
  10. Tom

    We should import a slew of honey badgers. They don't care, and they'll eat all the snakes.

    January 31, 2012 at 5:51 pm | Report abuse |
  11. Warp7

    They need to start doing some research and determine who bought snakes over the past year and determine what they did with them. Those who released them in to the wild need to be prosecuted. Open a snake season and let the hunters clean the marsh of the snakes.

    January 31, 2012 at 6:12 pm | Report abuse |
    • slickterp

      Purchases aren't regulated, it's impossible to track. Of course, I'm sure you want your tax dollars goign to the massive expenditure this would be.

      January 31, 2012 at 6:24 pm | Report abuse |
    • Pulsedpower

      They also escaped when hurricanes damaged homes. This is nothing new. One was on Jonny Carson twenty years ago. Found under a house by an exterminator.

      January 31, 2012 at 6:27 pm | Report abuse |
  12. Jataka

    Lot of stupid people on here. Let loose honey badgers? Crossbreed a mongoose with a grizzly? How the hell do Assburgers get a hold of a computer?

    January 31, 2012 at 6:13 pm | Report abuse |
    • Killing_time

      Dude calm down. These remarks are obviously tongue-in-cheek and stated for a laugh, not to get them implemented.

      January 31, 2012 at 6:26 pm | Report abuse |
    • jackyankee

      the same way you got on, weaniewaver

      January 31, 2012 at 7:32 pm | Report abuse |
  13. James

    Open season !

    January 31, 2012 at 6:15 pm | Report abuse |
  14. dicerotops

    Allow for hunting of pythons. Have annual python fairs where there are contests for the most pythons caught, the biggest one caught, etc. Sell the meat, use the skins.

    January 31, 2012 at 6:36 pm | Report abuse |
  15. gahh

    Offer a bounty for every one killed, and kill them all. The majority of people hate snakes.

    January 31, 2012 at 7:13 pm | Report abuse |
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