It slides quickly through the water.  It is 20 feet of strong muscle, every inch deadly.  It's huge, smiling mouth bears 3-inch razor sharp teeth.  It is a Great White Shark, the fiercest killer in the sea.  People have always been afraid of sharks.  After the movie Jaws came out, they were even more afraid.  And they are right to be.  Each year, sharks kill about 50 people.  One shark was so hungry it tried to eat a man whole.  It choked when the man stuck in it's throat.  People aren't the only things sharks like to eat.  They'll eat anything, from a whole horse to tin cans-- even bikes.  All this can be pretty hard on a shark's teeth.  But don't worry about some poor old shark losing his teeth and going hungry. Sharks have an extra set of teeth. When one row wears away, another row moves into place.  A shark may go through 200 teeth in a year. So they're ready to gobble up any snack they find. Let's hope that snack isn't you!