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Under Attack

On a small motorboat in the warm waters off Honolulu, Hawaii, Carl Meyer is attempting an unusual rope trick. He is trying to lasso a shark! A young 6-foot tiger shark has been lured to his boat with a baited hook. Meyer, a graduate student at the University of Hawaii, manages to tie the monster to the boat and flip it over onto its back. The shark grins. Hundreds of razor-sharp, triangular teeth glisten in the sun. As Meyer begins to measure the shark and mark it with a plastic tag, he whispers over and over, "No biting, no biting, no biting!"

Humans hacve always been afraid of sharks. But the work of researchers like Meyer show that we have much to learn, and not so much to fear, from these sleek predators. In fact, it's sharks who are under a scary attack--by humans.

Shark Attack!
Wait a second. Shouldn't we worry about sharks' eating us? Not really. While movies and fish stories make us wary of sharks' mighty jaws, shark attacks are pretty rare. In a bad year, sharks may kill 10 or 15 swimmers worldwide, mostly by mistake. Great whites prefer high-fat prey such as seals. But people's wet suits, flippers or flapping feet may look like a seal or a fish to a hungry shark.

Humans, on the other hand, have developed quite a taste for shark steaks and shark-fin soup. Some people like to wear leather made from shark hides; others buy health products made from sharks' body parts. A few have even paid thousands of dollars to decorate their home with shark jaws. Fishermen kill between 30 million and 100 million sharks each year. Many are caught accidentally in tuna and shrimp nets.

Because of this slaughter, the population of some sharks has dropped as much as 80% in the past decade. "At the current rate," says scientist Merry Camhi, "some species will reach extinction within 10 years."

Kings Of The Sea
Sharks have been swimming the planet for 400 million years. They were around more than 100 million years before dinosaurs appeared. Sharks have adapted to an amazing range of environments, from the Arctic to the tropics. The bull shark is known to hang out in rivers and lakes as far as 2,000 miles from saltwater.

Sharks are impressive creatures. Their simple immune systems fight off disease, especially cancer, better than humans' do. "Sharks have low-tech bodies," says scientist John Marchalonis. "But they do a good job."

Sharks also do a good job at keeping aquatic wildlife in balance. Most sharks are at the top of the food chain, the ocean equivalents of lions. They help keep other populations at the right size and strength. Removing sharks from the food chain, says Sonja Fordham of the Center for Marine Conservation, "could be disastrous." For instance, when overfishing killed off sharks near Australia years ago, the population of octopuses--a favorite shark treat--exploded. That threatened the spiny lobster, which octopuses love to eat.

Smooth Swimming Ahead?
Researchers hope a greater understanding of shark behavior will help protect sharks from human predators. For example, scientists in Hawaii hope to track the eating and travel patterns of hammerheads and tiger sharks by tagging them with electronic sensors. Among the discoveries: tiger sharks can dive 1,000 feet down and back up in just 15 minutes. They can also swim for miles in a perfectly straight line.

Medical researchers are also studying the shark. They believe its amazing ability to resist disease can teach us lessons about fighting human sicknesses.

Governments are working hard to cut down on shark hunting. The U.S., Australia, New Zealand and Canada have all placed limits on shark catches. "It's having an impact," says Rebecca Lent of the U.S. National Marine Fisheries Service. "The rate has slowed down." In August, California banned fishing of white sharks in state waters.

Conservationists have put seven kinds of sharks on the list of threatened species and have called for stricter rules before it's too late. "We should be concerned about protecting our resources," says scientist Gilbert Van Dykhuizan. "Sharks are here for a reason, not to attack men, women and children."

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Did You Know?

• SHARKS' teeth are disposable. Some teeth are lost with every bite, but new ones move forward to replace them.
• SHARKS have no bones. Their skeletons are made of cartilage, the flexible material in our noses.
• SHARKS can be as long as 50 feet (the basking shark) or as short as 5 inches (the dwarf shark).
• SHARKS use as much as two-thirds of their brain to sniff out prey.
• SHARKS don't chew their food. License plates, paper cups and entire animals have been found inside them.
• SHARKS' scales are actually tiny teeth called denticles.

Next: A New Set Of Eyes On Mars