Sharks Confuse People for Birds: Report

Certain sharks appear to confuse some recreational water users with birds, suggests a new case report that investigated a shark attack in the South Pacific.

The report, published in the Journal of Forensic and Legal Medicine, indicates that kitesurfers may be particularly at risk of becoming shark food.

At least, that's what appears to have happened to a 15-year-old male kitesurfer who died May 21, 2011 after encountering a tiger shark in waters off the city of Koumac on the northwest coast of New Caledonia.

"We hypothesize that the shark may have confused the motion of the kitesurfer, who was pulled by his kite without the board, with a bird overtaking the water," lead author Eric Clua, a marine biologist and veterinary surgeon based in French Polynesia, told Discovery News.

Clua, along with co-authors Pierre-Marie Bescond and Dennis Reid, studied the remains of the victim to better determine why exactly the shark attacked. The location in the water, nature of the attack, and tooth impressions on the body revealed that the bites were made by a nearly 10-foot-long tiger shark.

The authors mentioned that "when a kitesurfer does lose his board and is pulled by his sail (kite) along the surface, such as in the present case, with relatively high speed and intermittent touching down on the surface, it could represent a strong feeding stimulus for a shark."

Unlike marine mammals, sharks learn to navigate their surroundings and survive by experimenting, usually through trial and error. Tiger sharks and certain other sharks are known to feast on birds, as well as sea snakes, fish, turtles, marine mammals and more, according to National Geographic.

Clua added that attacking humans "is a problem of individual behavior of some sharks, not of a given species and even less for sharks in general."

Tiger sharks are one of the top three sharks implicated in unprovoked attacks around the world, the NOAA reports, behind great whites which are number one.

This may be because tiger sharks are highly visual predators who forage on air-breathing animals, Austin Gallagher, a researcher at the University of Miami's Abess Center for Ecosystem Science and Policy, told Discovery News. It also could be because they have a near completely undiscerning palate, and are thus unlikely to swim away after biting a human, National Geographic notes.

"The sea is not a zoo where you go to see dangerous animals without any chance of being wounded," Clua concludes. "If you go to sea, you must accept the rules and risks."