There are 375 known species of sharks. All sharks have bones made from cartilage. Sharks are fish, but unlike fish they can't swim backwards. Most sharks live in either cold or warm salt-water oceans, but the Gangas and the bull sharks sometimes swim up freshwater rivers.

Sharks have existed longer than dinosaurs. Although they don't look alike, saw fish, guitar fish, and rays are the shark's closest relatives. A shark's jaw has about five or six rows of teeth. Sharks can't chew with their teeth, but they can grind, grip, and rip their prey with their teeth. Sharks mainly prey on fish, but they also prey on seals and sea turtles. More than half of the shark's brain is used to smell. Some sharks can smell blood 500 feet away.

return to beginning page