Shark Hallmarks: Although the great white shark is probably the most famous of this group of talented hunters and voracious eaters, sharks come in many different sizes, shapes and colors. In general, however, the torpedo-shaped body and sharp rows of teeth are the hallmarks of the shark.
Exceptions to the Rule: Some exceptions are the frill shark, a deepwater species, which resembles an eel more than a shark. Another variation is the pygmy shark, which grows no larger than 10 inches in length. The pygmy has light-producing organs on its belly and sides. It is thought that this its luminescence eliminates shadows, making this shark difficult to see when attacking its prey.
Hunting Techniques: Different species also depend on different tactics for hunting and killing. Some sharks rely on short high-speed chases. Other species prefer to wait for sedentary fish to come their way, and still others are scavengers on the look out for carcasses.
In Decline: The popularity of shark fishing and shark as food have had an impact on populations. About 100 million sharks are caught annually.
