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Handling a bite that feeds him

By TERRY TOMALIN, Times Outdoors Editor
Published September 7, 2007


Oh, the shark, babe, has such teeth, dear

And it shows them pearly white.

Mack the Knife

Nothing instills fear in humans like the sight of a shark, mouth open wide, poised to rip off a pound of flesh.

Maybe that's why Bobby Darin's 1959 hit struck a nerve with people and stayed at the top of the charts for nine weeks.

Ya know when that shark bites, with his teeth, babe

Scarlet billows start to spread.

But while MacHeath had his jackknife, it could never compare with the real slicers and dicers of the animal kingdom. Sharks may not "swallow you whole" as Capt. Quint forewarned in Jaws he actually was bitten in half but they will tear off a limb if given a chance.

"It is pretty amazing that animal made out of soft cartilage and not hard bone could bite so hard," said marine biologist Dan Huber of the University of Tampa, who makes a living studying sharks. "They shouldn't have so much power."

Shark man

Huber grew up on Long Island, where fishing is a way of life. Its far eastern tip, Montauk, is a mecca for anglers who hunt sharks for sport. One local, Frank Mundus, is widely credited as being the inspiration for Peter Benchley's Quint.

"The thing about a shark ... he's got lifeless eyes," Quint tells his mates aboard the Orca as they search for the monster great white. "Black eyes. Like a doll's eyes."

Huber has gotten close to many species of shark.

"The big ones are hard to study," he said. "You don't get a chance to interact with many live specimens."

Sharks have long been called "the perfect predators," in part because of the 3,000 or so serrated teeth that enable the big meat-eaters such as the great white to tear off huge chunks of flesh.

"If you are a shark guy, you want to study the biggest and the baddest," the 28-year-old assistant professor said. "To do that, you have to go to Australia."

Nasties

In Australia, surfers call sharks "nasties." Of that bad bunch, the great white gets the most respect.

In July, Huber, who studied at both Duke and South Florida, got a call that an 8-foot shark had become entangled in netting used to protect local beaches. Huber quickly flew to Australia, where he dissected the shark and performed a CAT scan on the great white's head.

"All that information was fed into a computer, which we used to create a digital shark," he said. "We were able to create a model that shed some insight into the mechanics of how a shark bites."

(To see a 3-D image of Huber's "bite force" model go to ut.edu/public_info/3D-white.gif.

Surfers, swimmers and scuba divers won't be the only people to benefit from Huber's research. A sound understanding of how a shark bites will help the industry design shark-proof transoceanic cables and shark-resistant armor and underwater cages.

The big three

The Australian shark was Huber's first and only great white. But he also has studied bull and tiger sharks, which, along with the white, are responsible for the most fatal attacks worldwide.

The tiger and great white are rare in area waters. The latter usually are associated with colder waters where they feed upon sea mammals such as seals, but occasionally Gulf Coast commercial fishermen catch great whites during the winter months on bottom long lines.

The tiger, a tropical species, is also a large shark, capable of crushing a sea turtle shell in one bite. The bull, another thick-bodied beast, is the most common dangerous shark in area waters and will eat just about anything, including other sharks.

"If I was going to put the three of them to a test, I would say the bull or tiger probably has the strongest bite," Huber said.

The bite-o-meter

Scientists can measure the force of a shark's bit with a device called the gnathodynamometer. According to the Discovery Channel (the folks who bring you Shark Week), a single shark tooth can exert a pressure of 132 pounds. Since this is spread over a large area (remember, lots of teeth), a shark's jaws would exert a pressure of about 3 tons (more than 6,000 pounds), more than enough to chomp Quint clean in half with one good bite.

Terry Tomalin can be reached at tomalin@sptimes.com or (727) 893-8808.

FAST FACTS

Bite forces

Dr. Brady Barr of the National Geographic Channel measured this for the documentary Dangerous Encounters: Bite Force:

A domestic dog has a bite force of 317 pounds.

A lion has a bite force of 691 pounds.

A hyena has a bite force of 1,000 pounds.

A snapping turtle has a bite force of 1,004 pounds.

A Florida crocodile has a bite force of 2,500 pounds.

Caryn Baird, Times news researcher