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. jerryS

    Python skins sell for $130 a piece. If someone in florida is smart, they'll start hunting pythons. NO license needed to kill non native species. You can easily sell the tanned pelts online. 10,000 snakes in one park. That's 1.3 million dollars.

    January 31, 2012 at 11:37 am | Report abuse |
  2. Dan Bednarik

    Yet, they still allow people to own these snakes - Stupid really. Nobody except a zoo should harbor large reptiles or any exotic animal for that matter. These snakes need to be killed off, not saved.

    January 31, 2012 at 11:39 am | Report abuse |
    • Jim

      Anyone who owns a potentially deadly animal should be charged with pre-meditated murder also, if their "pet" ends up killing someone.
      Python, poisonous spider, pitbull....whatever.

      January 31, 2012 at 12:05 pm | Report abuse |
  3. ANGEL

    why is it always the creatures we hate the most that overpopulate and never die out, like Snakes, mice, Bugs or rats!!

    January 31, 2012 at 11:42 am | Report abuse |
  4. Christine Logan

    Are they partial to humans mabe they can bring them over here see if they can wipe out those in parliment

    January 31, 2012 at 11:42 am | Report abuse |
  5. Harley98c

    With Federal Aid, why not open a hunting season for the snakes. Offer a reward and pay by the pound. With unemployment being high in most states, I am sure there would be a couple thousand hunters willing to huntthese sankes down until they are no longer a problem. ..

    January 31, 2012 at 11:46 am | Report abuse |
  6. ceg

    You mean this story of python snakes in Florida has been going on for 11 years and just a month ago they decided to ban the snakes importation??? For 11 years they knew about this problem.....Whose running the government down there? When we have a deer population problem here we authorize a longer deer hunting season and up the limit of deer you can kill. Hint hint, authorize snake hunting year around and wipe them suckers out! I wonder how long its going to take before they make that law...

    January 31, 2012 at 11:47 am | Report abuse |
    • Aeromechanic

      Jeb Bush was in charge for quite a while. He is a hillbilly so he probably had python as a pet.

      January 31, 2012 at 12:14 pm | Report abuse |
  7. Robert

    The comments on this article point to a severe need for education. If the snakes are not even found in the northern regions of the park, and, according to "scientists" like Dorcas, are eating everything in sight, why have they not expanded northward. The answer is simple. They can't. These are tropical creatures that cannot stand the colder temperatures.

    January 31, 2012 at 11:48 am | Report abuse |
    • Michael

      Actually, they CAN withstand colder temperatures, but they need warmer temperatures in order to reproduce. So they can live further north, but since they can't reproduce in cooler temperatures their population cannot grow and expand north. Piranhas can survive in water as cold as 50 degree F, but need temperatures in the 70's in order for their eggs to develop and hatch.
      I have a masters in zoology and one of those "scientists" you're referring to.

      January 31, 2012 at 11:58 am | Report abuse |
    • Chris R

      So what you are saying is that we shouldn't listen to people who study things like this for years and years. Instead we should listen to some random person on the internet? Listen, the northern reaches of the park aren't really any colder than the southern areas. The everglades are a large park but they don't span a huge north south region – it's basically from the tip of Florida up to Miami. Maybe 50 miles north south. You aren't going to see a temperature differential large enough to prevent the snakes from spreading that far north. So why haven't they? Because the spread of the species just isn't that fast. It's only been around ten years and individual pythons don't have a huge hunting range. This means it will take time for them to expand to the north – however, if nothing is done they certainly will in time.

      January 31, 2012 at 11:59 am | Report abuse |
  8. JaneDoe

    First, we need to end importation of any wildlife from any country into the U.S. Second, the government needs to pay hunters to kill these creatures ... . It is cheaper to do that now than to allow these creatures to come into neighborhoods and hide in yards. Eventually, they will hunt other food sources like pets and children.

    January 31, 2012 at 11:48 am | Report abuse |
  9. Jim

    Why not put a boutny on the a certain amount for each carcass....
    The problem will be solved in no time!
    Tired of hearing Florida whine about it......start killing them off.

    January 31, 2012 at 11:50 am | Report abuse |
    • apostate

      the bounty idea is good, you will have every Cletus and Brandine in a 200 mile radius out there hunting these snakes.

      January 31, 2012 at 11:59 am | Report abuse |
  10. jlynn

    I just dont understand why u people have to be so mean I,come on saying things like feeding babies and homeless and other human beings is a disgrace under god with additudes like that they only thing that is going to be feed on is your soul will your buring in hell.ignrance is a real problem and I dont know why cnn dont filter these blogs.

    January 31, 2012 at 11:53 am | Report abuse |
  11. Buster Bloodvessel

    That kid does this every so often, posting about Mormons and snot and feces. CNN ought to ban his IP. He stops when he goes to school and starts again in the afternoon. Product of a broken home.

    January 31, 2012 at 11:56 am | Report abuse |
  12. Mikey

    Sounds like the battle is already over. Won't all the pythons die off when there's nothing left to eat?

    January 31, 2012 at 11:56 am | Report abuse |
    • Durundal

      Die, migrate, adapt to new sources, who knows. In either case its not going to be pretty

      January 31, 2012 at 12:08 pm | Report abuse |
    • The Woof

      The next target will be humans. Think about it, when you get hungry don't you go out and try to find something to eat if there's no food readily available? This what happens when humans start messing with the natural order of things. We have killer bees because some jerk thought it would be cool to mix two species of bees.

      January 31, 2012 at 12:08 pm | Report abuse |
  13. Anonymous

    If you have a flat, keep going until you see a restaurant or service station. If your dog needs to pee, let it pee in the car If your car stops, don't get out.

    It sounds very dangerous.

    January 31, 2012 at 11:56 am | Report abuse |
  14. Charms

    how about having a controlled python hunting season? If they are destroying the ecosystem, try to restore the balance.
    I hate snakes anyway lol

    January 31, 2012 at 11:58 am | Report abuse |
    • The Woof

      This is one time I'd wholey support a controlled kill but this sounds like it will take a long time. But on the bright side we're whining about unemployment in this country this is a win-win situation. To cover an area that size will take a heck of a lot of manpower and thereby open up a heck of a lot of jobs LOL!

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

      You might be able to hunt down a lot of the big ones, but there will be many times more little ones hiding under rocks.

      January 31, 2012 at 12:17 pm | Report abuse |
    • PushingBack

      The Woof – the only problem with your suggestion is that would require taxpayer money and nobody wants that these days. I guess you were suggesting a socialist snake hunting party be formed!

      January 31, 2012 at 12:17 pm | Report abuse |
  15. RamessesII

    I completely agree with putting a bounty on the snakes and turning hunters loose in the 'Glades. HOO RAH! And a Semper Fi to y'all!

    January 31, 2012 at 11:59 am | Report abuse |
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