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Tuesday, August 27, 2013

SCIENCE NEWS - THRESHER SHARKS #3

THRESHER SHARKS


They’re called thresher sharks. But perhaps thrasher is more accurate. Because a population of these fearsome predators was spotted engaging in an unusual hunting strategy.
Forget jaws—try the other end. Researchers observed them slapping their long, scythe-like tails at high speeds through the water. These whaps stunned or killed several smaller fish with each strike. The observations were made off the coast of the Philippines.
Killer whales and dolphins also may use a similar tail-slapping strategy. But this is the first time the behavior has been seen in sharks.
Although the formidable, three-meter-long pelagic thresher shark seems able to catch food face-first, the ability to immobilize more than one fish at a time makes the method highly efficient. The findings are in the journal PLoS ONE. [Simon P. Oliver et al., Thrasher Sharks Use Tail-Slaps as a Hunting Strategy]
These sharks used both vertical and horizontal tail slaps to capture prey, which were stunned or killed either by direct impact or by a shockwave from the smack. More than a third of the vertical slaps resulted in a meal for the shark—better stats than when sharks chased prey head on. And that's no tall tale.
—Katherine Harmon