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. JAMISON

    Time to have a Python hunting season in the Everglades.

    February 1, 2012 at 9:09 am | Report abuse |
  2. peter

    Non native species should NEVER be allowed for personal sale in any country. Any one who ever purchased one should turn them in and a bounty placed on each Python etc killed and turned in as well as the idiots who purchased these damn things, g&^%$n , people are so friggin dumb and selfish!

    February 1, 2012 at 9:09 am | Report abuse |
  3. jdun

    1. Disallow transport of all non-native species into the USA. That includes bireds, fish, mammals and reptiles. 2. Put a bounty on non-native snakes to encourage hunting them. Pretty soon we will be reading about missing kids in Florida if these snakes aren't eliminated. Unlike native species like rattlesnakes these snakes do not contribute to the balance of nature and must be eliminated.

    February 1, 2012 at 9:16 am | Report abuse |
  4. PumpNDump

    Simple solution: Kill the snakes, just as we do wild pigs. Both are vermine.

    February 1, 2012 at 9:21 am | Report abuse |
    • SnakeitorLeaveit

      I agree with pretty much everyone else here. Simple solution. These snakes aren't intended to be there. Get permits and start allowing people in to kill them and keep the skins. Like alligators etc. You can't OVER hunt them I don't think since there isn't a desire to have them there at all. I think a few seasons of hunting and selling the snake skins will decimate the numbers and the area can work towards rebuilding.

      February 1, 2012 at 10:18 am | Report abuse |
    • stephanie

      If people are permitted to hunt these large snakes, we're going to start getting stories about hunting accidents. Leave it to the professionals to capture them.

      February 1, 2012 at 7:25 pm | Report abuse |
  5. Nick

    Doubt humans will ever get them all, but do as they do with the Alligator season in La. Allow hunters to purchase permits, which will generate revenue for the state, and allow a liberal bounty for each person and soon the snake problem will be under control....

    February 1, 2012 at 9:30 am | Report abuse |
  6. Glades2

    As someone who's lived here for most of my life and remembers my many trips to Everglades National Park before this happend, my only thing that comes to my mind is "what a shame" – because this is not something of God's Will for the Everglades, but man's sin that has brought this disaster upon the park and surrounding areas. Our lack of any substantial cold weather this winter has only made matters worse, because previous hard freezes in the past few years helped to reduce the exotic snake population, but that has not been the case this season. Washington needs to place this at the top of the to-do list for national parks, otherwise the Everglades will soon be nothing but a sawgrass prairie overrun by these dangerous creatures. What worries me is that nothing will be done until a human is killed – that's how things usually work out when it comes to the sin of indifference...

    February 1, 2012 at 9:56 am | Report abuse |
  7. Bob Knippel

    Every weed in my yard is non-native. So is the grass.

    February 1, 2012 at 10:19 am | Report abuse |
  8. mwenzel2

    This makes me sick how one human ignorance ruins a whole ecosystem. Can people just stop and think before they do something like release a nonnative to the wild. I hope these snakes will die out soon because I think we all would rather have more diversity in the everglades than one dominant snake.

    February 1, 2012 at 10:24 am | Report abuse |
  9. Gary

    Regrettably Man has been systematically destroying their own source of water, since Flagler arrived and placed Australian trees that can not burned (it releases its seeds into the wind when it senses fire), absorbs 30 times the amount of water of other trees, and grows compactly, effectively eliminating the natural makeup of this treasure.

    Man has also moved so far from the coast, taking yet more space, but then are surprised that there is an alligator in the swimming pool. So now the pythons have found the perfect location, and just evidence was showing a comeback for the much-loved manatees. There are so many species that live in that National Park, and the python will regrettably overrun the location.

    A culling of the python sounds simple on paper, but you must remember that there are other reptiles there, and the Everglades has a wide variety of plants that will cut you, like the Palmetto, the Sawgrass, and others. If you would need to escape quickly the blood trail and the damage to you might make you a meal, and if that doesn’t kill you the muck and waters are a breeding ground for some very nasty bacteria.

    I personally want to punch every idiot that threw their novelty pets into the Everglades. Its beyond illegal and stupid. It is infuriating.

    February 1, 2012 at 10:27 am | Report abuse |
  10. TomGreen

    As much as 99%? Huh? The methodology used to compile the results is so flawed the math is worthless. The conclusions are worthless. Might as well consult an astrologer. And tax dollars were used. Sad.

    February 1, 2012 at 10:28 am | Report abuse |
    • Kenny of Salt

      As long as the methodology is consistent from one count to another, then it will accurately reflect a directional trend in the data. So THERE, Mr. Smartypants!

      February 1, 2012 at 6:21 pm | Report abuse |
  11. James Crane

    Well it looks like their is gonna be a new reason for another show on the history channel.. Swamp People of the Everglades

    February 1, 2012 at 10:33 am | Report abuse |
    • stephanie

      There already is a show on NatGeo about this problem- it's called Python Hunters

      February 1, 2012 at 7:22 pm | Report abuse |
  12. Jim

    Sounds like they will be out of food soon

    February 1, 2012 at 10:35 am | Report abuse |
  13. james

    They have people killing the snakes you go hike around and see how easy it is to find rhem in the middle of nowhere. You cant stop importing every animal either that would negatively effect small business who make a living selling them proper education is the only way.

    February 1, 2012 at 4:41 pm | Report abuse |
    • Deb

      Yes we CAN (and should) stop the importing of non-native species. If you had extensively studies and appreciate the variety of species found in nature, you would understand that such importation for private ownership serves no beneficial purpose whatsoever. All it does is unbalance the ecosystem and wreak havoc. It's not fair to the animals imported, either, as their husbandry and medical needs are not met by those who buy them for the novelty or "cool" factor. Those "small businesses" you claim would go out of business are making their money unethically, and SHOULD go out of business. There are plenty other legitimate, ethical businesses they could go into instead.

      February 1, 2012 at 8:30 pm | Report abuse |
  14. Joe

    How about everyone in Florida gets a pair of snake skin boots and matching hat? Seriously, these snakes are endangered in their native habitat because of overhunting. How can the nation that wiped out the buffalo, wolf, bear, and nearly the north american alligator, until conservation efforts saved them, turn away from this challenge. We can wipe these things out in a few years if we call open season.

    February 1, 2012 at 4:58 pm | Report abuse |
  15. Hanes

    It is time to create and industry of boot and belt making and exporting snake meat

    February 1, 2012 at 6:18 pm | Report abuse |
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