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Posted at 04:04 PM ET, 01/12/2012

Do Gulf tiger sharks walk on land?

Researchers from Alabama’s Dauphin Island Sea Lab have just published a new study about finding the remains of land birds in the stomachs of tiger sharks. The study prompted at least one site to pose the slightly sardonic question: Do Gulf tiger sharks walk on land?


A tiger shark (ANDREA COMAS - REUTERS)
For better or worse, the answer is no. Sure, it’s interesting that the tiger sharks Marcus Drymon and his colleagues studied had consumed woodpeckers, swallows, tanagers and meadowlarks. But several shark scientists said that studies dating back to the 1970s have shown that sharks swimming in U.S. waters have eaten land birds for sustenance.

“This whole thing about tiger sharks eating land birds is nothing new,” said John Carlson, a research biologist with the National Oceanic and Atmospheric Administration’s Fisheries Service. He noted that researchers found wood thrushes and other birds in the bellies of sharks off Melbourne Beach, Fla., in the 1970s.

Carlson, who published a paper a decade ago showing that tiger sharks off South Carolina had fed on the salt marsh-dwelling clapper rail, said they may be moving closer to shore than scientists had previously thought. But strong winds might be blowing some birds offshore, he noted, which would make them “easy pickings” for nearby sharks. “They’re just laying on the surface.”

Mahmood Shivji, who directs the Guy Harvey Research Institute at Nova Southeastern University and has tracked tiger sharks with satellite tags, also noted that “many land birds migrate long distances and individuals often don’t make it.” After becoming exhausted, Shivji added, they “drop into the ocean, where they drown and get eaten by likely a variety of large fishes, including tiger sharks.”

He added that the sharks have “a diverse diet” which can include iguanas along with a host of other critters.

And don’t fear, Carolson said: Fearsome tiger sharks aren’t about to scramble up onto the beach and start consuming humans.

“They have no capability to walk on land,” he said. “They’d roll over on their backs and die.”

By  |  04:04 PM ET, 01/12/2012

Tags:  National, tiger sharks

 
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