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10/14 Wired: Science

Tuesday, October 13, 2009

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Giant Invasive Snakes Threaten U.S. Wildlife, People
October 13, 2009 at 6:18 pm

invasive_5-copy

Nine different species of exotic giant snakes, released into the wild by irresponsible pet owners, could pose a major threat to U.S. wildlife, according to a new report published today by the U.S. Geological Survey.

Although pet constrictors start out small and cute, the largest snakes can grow up to 20 feet long and weigh as much as 200 pounds. The enormous reptiles end up in the wild when they’re abandoned by overwhelmed owners, or when they use their impressive musculature to escape from inadequate enclosures.

Tens of thousands of giant Burmese pythons already inhabit parts of southern Florida, and now scientists say at least eight other species of giant snakes have the potential to breed and thrive in parts of the United States, threatening already-fragile native ecosystems and putting 150 endangered species at risk.

“They will eat almost every vertebrate of the right size, but they mostly prefer birds and mammals,” said USGS biologist Gordon Rodda, who co-authored the 350-page study. “We've pulled a number of endangered species out of their stomachs.”

In addition, Rodda said all nine species are large enough to kill an adult human, although fatalities are rare. For example, despite the large population of captive Burmese pythons in the United States, the first unprovoked fatal attack was recorded earlier this year, when a pet python escaped from its cage and killed a 2-year-old child.

“There have been recorded fatalities from these species,” Rodda said. “Personally, I don't think it's a big deal, but if I had a small child, I would be mindful of that risk if the child was in an area where there might be pythons.”

invasive_02Individual snakes from all nine species have been found in the United States, but so far only three species — Burmese pythons, boa constrictors and northern African pythons — have established breeding populations in the wild, all currently confined to southern Florida. Based on the snakes’ preferred climate range, potential ecological impact and prevalence in trade and commerce, the report classified five species as high risk and the other four as medium risk to native ecosystems.

A preference for warm weather means most of the snakes could only survive in Florida, southern Texas, Hawaii or tropical islands like Guam and Puerto Rico. Still, Rodda said a few species could potentially spread throughout many of the southern states. “The most temperate of the species is the Burmese python,” he said. “That's the one that really goes up both coasts and across the southern U.S.”

The hardy animals tolerate urban and suburban environments quite well, and boa constrictors and northern African pythons have both been spotted in the Miami metropolitan area.

Unfortunately, once invasive snakes have taken hold in a particular region, the researchers say they’re almost impossible to get rid of, in part because elaborate camouflage makes the snakes very hard to spot. Some progress has been made in terms of radio-tracking and trapping the snakes, but despite several years of effort, Florida’s population of Burmese pythons and boa constrictors shows no sign of shrinking.

“At this time, we have no tools that would likely suffice to eradicate a big population of snakes once they had spread,” said USGS biologist Robert Reed, the other co-author of the study, who presented the findings today at a congressional briefing. “Instead of looking at the pound of cure,” he said, “maybe it's time to look at the pound of prevention.”

The results of the study, along with more than 1,500 public comments solicited by the Department of Interior, will be used by the U.S. Fish and Wildlife Service to decide how to prevent further spread of the giant constrictors. One option would be to place them on a list of injurious species under the federal Lacey Act, which would make it illegal to import the snakes or carry them across state lines.

Of course, reptile enthusiasts don’t want to curb the sale of these exotic snakes, and the researchers point out that owning a snake has educational value. “We can testify to these snakes’ attraction personally, as we both have kept pet giant constrictors,” the scientists wrote. “Thus the social value of protecting native ecosystems must be weighed against the social value of fostering positive attitudes about the protection of nature through giant constrictor ownership.”

Regardless of whether these giant snakes are eventually classified as injurious, the Fish and Wildlife Service says they’re taking steps to reduce breeding populations in Florida and prevent further snake invasion.

“It’s going to take a huge public education and outreach initiative to make people understand the value of being responsible pet owners,” said FWS spokesperson Ken Warren. “We don't pretend that there's any easy solution, but no action is not an option.”

Image 1: Burmese python (Python molurus). Roy Wood/National Park Service.
Image 2: A researcher measures the length of a captured Burmese python. Lori Oberhofer/NPS.

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Jupiter Moon's Ocean Could Be Rich in Oxygen
October 13, 2009 at 2:49 pm

europarise

FAJARDO, Puerto Rico — If there are any fish on Jupiter's moon Europa, they can breathe easy.

sciencenewsResearchers hunting for signs of life beyond Earth have long been drawn to Europa because several features of the moon's icy surface — including its bright color, networks of long fractures and crater-free terrain — suggest that the moon contains a vast ocean buried under the ice. Now one researcher has calculated that the proposed ocean may receive about 100 times more oxygen than previous models indicated — enough to support respiration by 3 million tons of fish or their Europan equivalent.

Oxygen, generated by charged particles striking water molecules on the moon's surface, would take 1 to 2 billion years to begin seeping into the ocean, calculated Richard Greenberg of the University of Arizona in Tucson. That delay would have been critical for supporting life because it would have allowed time for primitive organisms to develop the ability to use oxygen. If oxygen instead had been immediately released into the ocean, it would have destroyed fledgling life through the well-known process oxidation, commented Jonathan Lunine, also of the University of Arizona, who was not part of the study.

Greenberg reported the findings October 9 at the annual meeting of the American Astronomical Society's Division for Planetary Sciences.

Theorists had previously calculated that the charged particles striking Europa would produce oxygen within the top few centimeters of the moon's crust. Small impacts from space debris would then kick up material that would bury this oxygenated layer to a depth of a few meters. The new part of the story, said Greenberg, came when he considered Europa's youthful, nearly crater-free appearance. The paucity of craters indicates that the crust is continually resurfaced. Today's crust is only 50 million years old, even though the moon formed soon after the solar system's birth 4.56 billion years ago.

Over a period of about 50 million years, a layer of ice 300 meters thick slowly rises from below, eventually covering the moon's surface and erasing old craters, Greenberg suggested. As a result of this facelift, Europa's oxygenated layer grows increasingly thick, until after about 1 to 2 billion years the entire ice layer is oxygen-rich, Greenberg said. At that point, ice melting at the bottom of the frozen layer would begin delivering oxygen into the buried proposed ocean at a faster rate than previously estimated, resulting in about 100 times more oxygen in the ocean.

Image: NASA

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Monkeys Fall Into 'Uncanny Valley,' Just Like Humans
October 13, 2009 at 1:44 pm

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Monkeys are freaked out by almost-but-not-quite-real depictions of themselves. That tendency is well documented in humans, but has never before been seen in another species.

To test their preference, researchers showed macaque monkeys real pictures, digital caricatures and realistic reconstructions of other monkey faces. To the latter, the macaques repeatedly averted their eyes.

“The visual behavior of the monkeys falls into the uncanny valley just the same as human visual behavior,” wrote Princeton University evolutionary biologists Shawn Steckinfinger and Asif Ghazanfar in a paper published Monday in the Proceedings of the National Academy of Sciences.

uncanny-graphThe “uncanny valley” was identified in 1970 by Japanese roboticist Masahito Mori, who noticed that people presented with likenesses of increasing realism respond with increasing empathy, right up to the point where the likenesses are almost real. At that point, people are repulsed. The sudden dip in graphs describing their response gave the phenomenon its name.

Many explanations have been suggested for the uncanny valley, which has also been blamed for the box-office failure of movies like Beowulf and Final Fantasy. Perhaps almost-real humans look a bit too much like corpses for our comfort; perhaps they’re so real that they engage our brains’ mate-recognition or disease-avoidance systems, which promptly identify poor partners or sick individuals.

The PNAS results don’t favor any one of these explanations, but do suggest that the uncanny valley has evolutionary origins deep in the primate psyche.

It remains to be seen how the monkeys would react to a simian version of The Polar Express.

Images: PNAS

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Citation: “Monkey visual behavior falls into the uncanny valley.” By S. Steckenfinger & A Ghazanfar. Proceedings of the National Academy of Sciences, Vol 106. No. 40, October 12, 2009.

Brandon Keim’s Twitter stream and reportorial outtakes; Wired Science on Twitter. Brandon is currently working on a book about ecosystem and planetary tipping points.




Galactic Hookup Spawns Celestial Offspring
October 13, 2009 at 10:02 am

crazydoublegalaxy

This bizarre-looking two-armed galaxy, captured by the Hubble Space Telescope, is actually two spiral galaxies in a high-speed collision 250 million light-years away.

The crash and resulting mixing of mass and gas sparked new star birth that is visible in the arms. The arm on the right also has many star clusters that are brighter than anything nearby our own galaxy.

 This star merger is taking place in the constellation Cancer and is known as NGC 2623. Because it is so bright in the infrared, it belongs to a group of galaxies known as luminous infrared galaxies (LIRG) being studied in the Great Observatories All-sky LIRG Survey (GOALS) project. 

Image: NASA, ESA and A. Evans (Stony Brook University, New York)

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