Pythons suspected of killing mammals

2012-01-31 13:00
A Burmese python is wrapped around an American alligator in Everglades National Park. (Lori Oberhofer, National Park Service, AP)

A Burmese python is wrapped around an American alligator in Everglades National Park. (Lori Oberhofer, National Park Service, AP)

Multimedia   ·   User Galleries   ·   News in Pictures Send us your pictures  ·  Send us your stories

West Palm Beach - A burgeoning population of huge pythons - many of them pets that were turned loose by their owners when they got too big - appears to be wiping out large numbers of raccoons, opossums, bobcats and other mammals in the Everglades, a study says.

The study, published on Monday in the Proceedings of the National Academy of Sciences, found that sightings of medium-size mammals are down dramatically - as much as 99%, in some cases - in areas where pythons and other large, non-native constrictor snakes are known to be lurking.

Scientists fear the pythons could disrupt the food chain and upset the Everglades' environmental balance in ways difficult to predict.

"The effects of declining mammal populations on the overall Everglades ecosystem, which extends well beyond the national park boundaries, are likely profound," said John Willson, a research scientist at Virginia Tech University and co-author of the study.

Tens of thousands of Burmese pythons, which are native to Southeast Asia, are believed to be living in the Everglades, where they thrive in the warm, humid climate.

Big

While many were apparently released by their owners, others may have escaped from pet shops during Hurricane Andrew in 1992 and have been reproducing ever since.

Burmese pythons can grow to be 8m long and weigh more than 90kg, and they have been known to swallow animals as large as alligators. They and other constrictor snakes kill their prey by coiling around it and suffocating it.

The National Park Service has counted 1 825 Burmese pythons that have been caught in and around Everglades National Park since 2000. Among the largest so far was a 70kg, 5m one captured earlier this month.

For the study, researchers drove 62 700km along Everglades-area roads from 2003 through 2011, counting wildlife spotted along the way and comparing the results with surveys conducted on the same routes in 1996 and 1997.

The researchers found staggering declines in animal sightings: A drop of 99.3% among raccoons, 98.9% for opossums, 94.1% for white-tailed deer and 87.5% for bobcats. Along roads where python populations are believed to be smaller, declines were lower but still notable.

Rabbits and foxes, which were commonly spotted in 1996 and 1997, were not seen at all in the later counts. Researchers noted slight increases in coyotes, Florida panthers, rodents and other mammals, but discounted that finding because so few were spotted overall.

"The magnitude of these declines underscores the apparent incredible density of pythons in Everglades National Park," said Michael Dorcas, a professor at Davidson College in North Carolina and lead author of the study.

Prime suspect

Although scientists cannot definitively say the pythons are killing off the mammals, the snakes are the prime suspect.

The increase in pythons coincides with the mammals' decrease, and the decline appears to grow in magnitude with the size of the snakes' population in an area. A single disease appears unlikely to be the cause since several species were affected.

The report says the effect on the overall ecosystem is hard to predict. Declines among bobcats and foxes, which eat rabbits, could be linked to pythons' feasting on rabbits. On the flip side, declines among raccoons, which eat eggs, may help some turtles, crocodiles and birds.

Scientists point with concern to what happened in Guam, where the invasive brown tree snake has killed off birds, bats and lizards that pollinated trees and flowers and dispersed seeds. That has led to declines in native trees, fish-eating birds and certain plants.

In 2010, Florida banned private ownership of Burmese pythons. Earlier this month, US Interior Secretary Ken Salazar announced a federal ban on the import of Burmese pythons and three other snakes.

Salazar said that the study shows why such restrictions were needed.

"This study paints a stark picture of the real damage that Burmese pythons are causing to native wildlife and the Florida economy," he said.
Read more on:    animals

Join the conversation!

24.com encourages commentary submitted via MyNews24. Contributions of 200 words or more will be considered for publication.

We reserve editorial discretion to decide what will be published.
Read our comments policy for guidelines on contributions.
NEXT ON NEWS24X

linking and moving

2015-04-22 07:36

24.com publishes all comments posted on articles provided that they adhere to our Comments Policy. Should you wish to report a comment for editorial review, please do so by clicking the 'Report Comment' button to the right of each comment.

Comment on this story
3 comments
Comments have been closed for this article.

Inside News24

 
/News

Book flights

Compare, Book, Fly

Traffic Alerts
There are new stories on the homepage. Click here to see them.
 
English
Afrikaans
isiZulu

Hello 

Create Profile

Creating your profile will enable you to submit photos and stories to get published on News24.


Please provide a username for your profile page:

This username must be unique, cannot be edited and will be used in the URL to your profile page across the entire 24.com network.

Settings

Location Settings

News24 allows you to edit the display of certain components based on a location. If you wish to personalise the page based on your preferences, please select a location for each component and click "Submit" in order for the changes to take affect.




Facebook Sign-In

Hi News addict,

Join the News24 Community to be involved in breaking the news.

Log in with Facebook to comment and personalise news, weather and listings.