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. MyOwnMind

    A hunt on the species to control the population is a great idea. Pay X amount per python as an incentive.

    January 31, 2012 at 3:22 pm | Report abuse |
  2. Floriduh

    If you're caught releasing an exotic lizard, iguana, or snake into the everglades, you should have to do community service down there. They should be dropped by helicopter and forced to wear nothing but a loin cloth and be given a burlap bag and a sharp stick. Maybe that will help clean up Floriduh's gene pool.

    January 31, 2012 at 3:24 pm | Report abuse |
  3. honey badger

    Honey badger don't care. Drop a dozen honey badgers in there, problem solved.

    January 31, 2012 at 3:29 pm | Report abuse |
  4. Smart Floridian

    How about preventing the problem as well? 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 3:33 pm | Report abuse |
  5. Floridian

    Stupid people shouldn't be allowed to vote. How about preventing the problem as well as solving it? I can tell you this issue has been going on for some time, and it's been reported in several forms of media. There's a similar problem that is happening all over the place. People buy animals and then 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 because selfish people and greedy companies WILL NOT DO THE RIGHT THING without being forced. People let pet birds go all the time to starve to death or be eaten by predators. Get some humanity people.

    January 31, 2012 at 3:37 pm | Report abuse |
  6. Floridian

    Stupid people shouldn't be allowed to vote. Go play your video game and stop blogging. How about preventing the problem as well as solving it? I can tell you this issue has been going on for some time, and it's been reported in several forms of media. There's a similar problem that is happening all over the place. People buy animals and then 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 because selfish people and greedy companies WILL NOT DO THE RIGHT THING without being forced. People let pet birds go all the time to starve to death or be eaten by predators. Get some humanity people.

    January 31, 2012 at 3:38 pm | Report abuse |
  7. nepawoods

    The common housecat, also an invasive species, is a greater threat to the Everglades than the pythons.

    January 31, 2012 at 3:53 pm | Report abuse |
    • us1776

      They're gone. The pythons ate them already.

      .

      January 31, 2012 at 4:24 pm | Report abuse |
    • TisJustMe

      So is the white man, another invasive species.

      January 31, 2012 at 4:39 pm | Report abuse |
    • Billiam Hillary

      TisJustMe = ignorant of history. The "red man" was the first invasive species of humans to invade north america.

      January 31, 2012 at 4:53 pm | Report abuse |
  8. Dave

    It is unlikely that the snakes represent pets that were let go by their owners – if this were the case we'd have problems with Burmese pythons in other warm swampy areas. It is much more likely that most of the snakes escaped from reptile warehouses in Florida when Hurricane Andrew struck as well as lesser storms.

    January 31, 2012 at 3:57 pm | Report abuse |
  9. Floridian

    How about preventing the problem as well as solving it? I can tell you this issue has been going on for some time, and it's been reported in several forms of media. There's a similar problem that is happening all over the place. People buy animals and then 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 because selfish people and greedy companies WILL NOT DO THE RIGHT THING without being forced. People let pet birds and bunnies go all the time to starve to death or be eaten by predators. Get some humanity people.

    January 31, 2012 at 3:58 pm | Report abuse |
  10. penturner

    Sometimes the solution is so simple. Put a bounty on the snakes or make hunters get a permit (money for the state) and let them shoot as many as they can. Then maybe some Entrepreneur will start a business making pocket books or something.
    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.” WHAT THE HECK DOES THAT MEAN AND WILL IT ACCOMPISH ANYTHING? Probably not

    January 31, 2012 at 4:00 pm | Report abuse |
  11. Floridian

    sorry about posting that so many times!

    January 31, 2012 at 4:02 pm | Report abuse |
  12. bigDizzle

    Um...can anyone say hunting season? People would eat snake meat and could sell snake hides for boots, purses, etc. It would also solve the snake problem. The state and county of the areas with the problem could benefit from not having to fund the hunts w/tax money and get extra revenue from hunting licensing (and getting the license could be contingent upon being able to correctly identify the breed of snake so as not to kill any other species which aren't such a big problem). I'm not a big fan of all kinds of hunting but this is the time and place for it if I've ever seen one.

    January 31, 2012 at 4:25 pm | Report abuse |
  13. TisJustMe

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

    And there, dear reader, is the solution. PETA = People Eating Tasty Animals

    January 31, 2012 at 4:36 pm | Report abuse |
  14. john cougar mellencamp

    There is also the reticulated python that they say is possibly mating with the Burmese python to make a hybrid more able to have the size of the one and the meanness of the other. oh well you know what happened when Indians got together with buffalos???

    January 31, 2012 at 4:48 pm | Report abuse |
  15. Merkat

    Dogs get ticks.

    January 31, 2012 at 4:50 pm | Report abuse |
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