‘What big teeth…’

What has 7-inch teeth, a mouth that’s 6 feet in diameter and can swim 35 feet per second? The giant white shark. But beach-goers need not fret, because this 60-foot monster shark has been extinct for millions of years.

“I don’t think 21-foot sailboats would be quite as popular if these sharks were still around,” says Bretton Kent, an instructor at the University of Maryland’s College of Life Sciences. “You’re talking about a shark who could’ve taken out one of Columbus’ smaller ships.”

For about two decades, Mr. Kent has been doing research on the giant white shark, which is estimated to be about three times larger than today’s top ocean predator, the 23-foot great white shark — a contemporary of the giant white several million years ago.

By studying fossils of the giant white shark’s teeth, Mr. Kent is trying to learn more about how this super predator lived and died.

Fossils are mineralized remnants or impressions of animals or plants from a past geologic age. The teeth, made of very durable dentine and enamel materials whose pores are full of mineralized materials, are basically all that’s left of these sharks. Their skeletons were made of cartilage that breaks down too quickly for soil sediments around them to harden into stone.

“But teeth can tell us a lot,” Mr. Kent says. “Just by studying teeth we can learn what they ate and how they attacked their prey.”

Stephen Godfrey, curator of paleontology at the Calvert Marine Museum in Solomons, Md., likens the study of fossils (teeth and others) to forensic science, since fossils give us clues as to extinct species’ behavior and appearance.

“When you study shark tooth marks on skeletal remains of other animals, such as whales and porpoises, it tells you that these sharks went for large prey,” Mr. Godfrey says.

One of the reasons researchers can tell that the tooth marks are from sharks is that the serration marks on the prey’s bone and those of the actual shark tooth match perfectly.

Mr. Godfrey and Mr. Kent have found dozens of fossilized giant white and other extinct sharks’ teeth at the Calvert Cliffs over the years. After spring thunderstorms, pieces of the cliffs break off under the pressure from the water. This frees up fossils that have been buried in the cliff.

Another sign that the giant white shark attacked large prey, up to 20 feet long, are the compression fractures on the shark teeth that Mr. Kent and other researchers have found.

“It indicates that they were biting down on large animals’ bones, sending ripples or shock waves through the teeth,” Mr. Kent says.

Animals have different attack strategies depending on the shape of their teeth. A modern great white probably would bite the prey with its razor-sharp — but not very big — teeth and then let the prey bleed to death before devouring it.

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