Now fill the bag with water and try again. Overview Unlike the ferocious star of Jaws , most sharks pose little danger to humans. The world's 370-plus species of sharks eat a variety of foods. Whale sharks gulp in water and filter it out through their gills, trapping tiny plankton for food. Cookie cutter sharks fasten onto prey, then twist and pull away flesh, leaving a hole like that made by a cookie cutter.
Nurse sharks use thick lips to suck food from rocky crevices.
A keen sense of smell helps sharks find food. Through touch, hearing, and sight, they detect movement in the water. A special organ on the snouts of sharks, called the ampullae of Lorenzini , allows them to detect weak electrical voltages from living creatures or ocean currents. Humans pose a greater danger to sharks than sharks do to humans. People kill about 100 million sharks each year, eating shark fin soup and shark meat, using shark oil cosmetics, wearing sharkskin boots and shark tooth jewelry, and using parts of the shark to make medicines.