Shark diet bad for orca's teeth

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Shark diet bad for orca's teeth

October 13, 2010 - 19:15
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Some orca whales have a surprising taste for shark meat, says a researcher at the Pacific Biological Station in Nanaimo, Vancouver Island. Their love for shark meat could be wreaking havoc with their teeth, reducing them to flat stubs, according to a study in Aquatic Biology.

An orca's teeth are ground down to the gum.

Until the 1990s, only two kinds of orcas were seen in the inshore waters of British Columbia, says John Ford, a zoologist at the University of British Columbia and a research scientist at the Pacific Biological Station run by Fisheries and Oceans Canada.: “resident whales,” which prefer delicacies such as salmon; and “transient whales,” which prefer to eat mammals such as porpoises and seals. The groups co-exist but don’t mix, socialize or mate, he explains.

But when the third kind of orca appeared off Haida Gwaii on the Queen Charlotte Islands, scientists were puzzled. The other whales had been photographed and individually identified by the natural markings on their fins. These whales appeared to be new. They were dubbed the “offshores.”

Shark eaters

Ford and his team of scientists then made a remarkable discovery: These whales love to eat shark. Scientists believe that their worn-down teeth is the result of eating famously tough-skinned sharks.

We started to speculate perhaps it’s sharks that they’re eating, and sharks have very rough skin—when it dries out, it’s like coarse sandpaper.”

Ford and his colleagues found leftover bits of meat that whales hadn’t eaten and took the meat to a molecular genetics laboratory for analysis. To their surprise, it turned out to be Pacific Sleeper shark.

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