Random Samples

Science  14 Aug 2009:
Vol. 325, Issue 5942, pp. 797

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  1. Double Trouble

    Rasmussen, L. colubrine, and H. pachycercos.


    The yellow-lipped sea krait (Laticauda colubrine), a venomous marine snake that prowls the Western Pacific and Indian oceans, has developed a clever tactic for warding off enemies even nastier than it is: It fools them into thinking it has two heads.

    The ruse combines skin markings and clever behavior patterns, biologists report online this month in Marine Ecology. While probing crevices and coral for food, the meter-long snakes temporarily drop their guard and become vulnerable to attack. But the krait appears to twist its tail around so that the black-and-yellow tip looks like a second head bearing an extra load of deadly venom. Other sea snakes, including Hydrophis pachycercos, seem to bear similar head-mimicking tail markings, the researchers say.

    “I think the two-head hypothesis is an interesting and credible idea,” says Martin Attrill of the University of Plymouth Marine Institute in the U.K. “Fish that sit around on reefs or the seabed … often have large ‘eye’ spots at the tail end to distract predators.” The krait is odd in another way, says Arne Rasmussen of the Royal Danish Academy of Fine Arts in Copenhagen, who led the study: Unlike most other sea snakes, it spends almost half of its time ashore. “It remains to be confirmed whether the kraits use their sea defense tactic of motioning their tails when on land,” Rasmussen says.

  2. Get a Grip!


    Despite their 91-kilogram heft, orangutans know how to live the high life, climbing from tree to tree 45 meters above the ground and snacking on fruit. It's tricky, though. The thinnest branches—twigs just a few centimeters across—tend to flex wildly and can cause fatal falls if they snap. But they're also located where fruit abounds and where the gaps between trees are the smallest, says Susannah Thorpe of the University of Birmingham, U.K.

    Over the course of a year, Thorpe and colleagues watched orangutans in a Sumatran rainforest traverse the treetops more than 2800 times, recording their motions and estimating—after much training to ensure accuracy—the diameters of the branches used during the animals' travels. The animals made the most of even flimsy branches, often grabbing handfuls of them to steady themselves as they moved, Thorpe's group reported in the 4 August issue of the Proceedings of the National Academy of Sciences. The researchers found that although half the size of male orangutans, females were more conservative, sticking to bigger branches, whereas males were the risk-takers. “Humans would have a really hard time navigating these small branches,” says Serge Wich, a primatologist with the Great Ape Trust in Des Moines.

  3. RIP ISS Tool Bag


    The world-famous $100,000 tool bag that astronaut Heidemarie Stefanyshyn-Piper lost in space last November finally met a fiery demise on 3 August. The backpack-sized bag—containing scrapers, two grease guns, some wipes, and a debris container—left Stefanyshyn-Piper's grip while she was cleaning a joint on one of the space station's solar panels. Amateur astronomers tracked the tool bag on Web sites and blogs, and some captured the time-lapse streak of its orbital track on film. In November, a hoaxer claimed to have found the bag on a golf course in Minnesota and briefly tried to sell it on eBay. No such luck for the real thing: NASA says the tool bag disintegrated completely in the atmosphere above the Pacific or Indian Ocean at about 10:30 a.m., EST. The tool bag will not be missed, a spokesperson for NASA said, as astronauts routinely drop space litter and let it burn up in Earth's atmosphere.

  4. Don't Hold Your Breath

    Competitive breath-holders can float face down in a pool for more than 4 minutes, and the world record is 11 minutes 35 seconds. That can't be good for their brains, right?

    To find out, researchers at Lund University in Sweden had nine trained breath-holders lie face-up on a couch and hold their breath to mimic the so-called static apnea pool competition. The breath-holders started with their normal warm-up routines: hyperventilation and “lung packing” (using tongue and throat muscles to force extra air into the lungs). Then they stopped breathing for an average of 5.5 minutes.

    The volunteers' blood oxygen levels dropped by almost 80%, and concentrations of the protein S100B—a standard marker for brain damage—increased by 37%, the researchers reported online 2 July in the Journal of Applied Physiology. S100B is normally found inside brain cells and fluid but seeps into the bloodstream when an injury disrupts the brain's protective blood-brain barrier. The breath-holders' concentrations were lower than those seen in stroke or traumatic brain injury patients, and the levels recovered after 2 hours. “We probably only saw a temporary opening of the blood-brain barrier,” says researcher Johan Andersson, but he warns that it is unclear if repeated barrier openings might produce long-term brain damage.

    Ralph Potkin, a pulmonologist at the Beverly Hills Center for Hyperbaric Medicine in Los Angeles, California, calls the findings “disconcerting.” But John Fitz-Clarke, a diving physiologist at Dalhousie University in Halifax, Canada, says that “it's way too premature to draw any conclusions about brain damage” from these findings.