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. Laura


    January 31, 2012 at 2:14 pm | Report abuse |
  2. scieng1

    The damage from feral and human-established invasive species, like hogs, "wild" horses, various fish, and snakes is destroying much of the natural ecosystems. A bounty may not be a bad idea, or allowing the use of skins and meat for food.

    January 31, 2012 at 2:28 pm | Report abuse |
  3. angeleyes

    How can you possibly inject politics into a snake problem in the Everglades? People buy these reptiles and when they get too big, they let them go, That has nothing to to with Republicans or Democrats! Get a Life

    January 31, 2012 at 2:37 pm | Report abuse |
  4. jp

    paid trappers $10 a snake....end of you problem....

    January 31, 2012 at 2:41 pm | Report abuse |
    • Chrissy

      100,000 x $10 = $1,000,000 -money the state does not currently have.

      January 31, 2012 at 3:29 pm | Report abuse |
    • Dianna

      If these snakes are hunted in their native areas for meat and skin, then we should have a market to sell these snakes to. Some enterprising folks down there in FL could start a new industry with the State of FL approval!

      January 31, 2012 at 3:35 pm | Report abuse |
  5. Wicket

    Not sure if previous post posted:
    Allow open-season on the pythons, a la feral hogs, sell/give the meat to foodies, declare python hide a trending fashion, and we can get rid of them. I would be happy to go python hunting in the everglades.

    January 31, 2012 at 2:46 pm | Report abuse |
  6. Wendy

    Once again...people destroy everything they touch. We cant be happy with a cute kitten or a dog as a companion, no, we have to be cool and get a snake or a big fat monitor lizard (yes they are down there too). Really, when people find out how hard it is to have a dog or cat, they throw them out, what makes you think they wouldnt do the same with a snake! No commitment to anything except for beer and cigarettes! people suck!

    January 31, 2012 at 2:48 pm | Report abuse |
    • Jim Bob

      Whoa. Take a chill pill...

      January 31, 2012 at 2:55 pm | Report abuse |
    • Xanthippe

      @ Wendy, you couldn't have said it more clearly! This is what it comes down to!

      January 31, 2012 at 6:22 pm | Report abuse |
  7. Bruce

    Hunting, hunting and more hunting. They must be wiped out. The everglades must be preserved. The pythons will wipe out millions of birds next. Shoes, belts and handbags yes! Live pythons in Florida no! Kill everyone of the pythons. $10 per snake seems like a reasonable place to start.

    January 31, 2012 at 2:50 pm | Report abuse |
    • Fly Guy in SJ

      Beyond the great threat they pose to the general Everglades (and beyond; the pythons are not confined to the 'glades) they also pose a threat to humans. AFAIK they have not yet eaten a person in Florida, but I want to stress the "yet" in that sentence. Large Burmese pythons are known to occasionally prey on humans in their native range. A child would be an especially vulnerable target, but a python is capable of swallowing an adult, too.

      Open season on pythons, with no limit, would go a long way toward constraining them. However, the Everglades are a national park, which probably means professional hunters will need to be brought in as exterminators. In the rest of Florida, we should definitely go for open season all year, no limit, on pythons. Maybe even pay a bounty, although the value of the meat and (especially) skin will probably be enough to encourage hunting.

      January 31, 2012 at 3:00 pm | Report abuse |
    • Chrissy

      most of the everglades is not easily accessible to even hunters.

      January 31, 2012 at 3:31 pm | Report abuse |


    January 31, 2012 at 2:51 pm | Report abuse |
  9. Drinker

    Cull them, bounty them. Get rid of the pet trade in snakes altogether.

    January 31, 2012 at 3:04 pm | Report abuse |
  10. vicki

    Would it be possible to capture the snakes and ship them to their native range? Otherwise I'd say kill as many as possible and like Tom THomas said, feed them to the homeless.

    January 31, 2012 at 3:04 pm | Report abuse |
  11. citizenUSA

    Sounds like a good reality show to me, "Hiss Hunters".

    January 31, 2012 at 3:09 pm | Report abuse |
  12. Boomer in Mo

    There are probably some jobless hunters in Fla. who would take a minimum wage job to kill the snakes full-time. And pay them a bonus if they get more than 10 snakes a day as an incentive. Might take 10 years to get all the snakes, but the sooner you start, the sooner they will be gone.

    January 31, 2012 at 3:13 pm | Report abuse |
    • nepawoods

      You really think hunters can hunt down every little baby python that's slithering under a rock or rotting log or some wet leaves in the entire Everglades?

      January 31, 2012 at 3:26 pm | Report abuse |
  13. Manwithworkingbrain

    I like how this story implies that these snakes are devouring so many deer and bobcats that the populations are depleting. Uh yeah right... Sorry it doesn't add up to a probable cause, but more BS that CNN calls reporting.

    January 31, 2012 at 3:14 pm | Report abuse |
    • I'm from Florida

      ... I can tell you this issue has been going on for some time, and it's been reported in several forms of media. It's a problem that is happening all over the place. People buy animals and them let them go when they figure out that it's "Too hard and too expensive" to care for them. That's why there needs to be regulation. Regulation exists for people and companies who WILL NOT DO THE RIGHT THING without being forced.

      January 31, 2012 at 3:31 pm | Report abuse |
  14. Do some research

    I wish people would at the very least read a book about the animal they plan to purchase and make a committment to caring for it once they do purchase it. Feeding it.... Vet care.... providing a home for decades... I'll be most people don't even realize that some parrots will out live them. It shouldn't be legal to buy or sell exotic birds and exotic animals. Even some domestic animals, like ferrets, are so inbreed that they will die from cancer and cost hundreds for vet care. Do yourself and your budget a favor before buying an animal and do some research. If people didn't buy the animals, they wouldn't sell the animals.

    January 31, 2012 at 3:14 pm | Report abuse |
  15. Floriduh

    I guess I'll go buy a snake and when I get tired of it, I'll let it go in the everglades.... jeeze.

    January 31, 2012 at 3:18 pm | Report abuse |
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