Sharks can come in many different sizes and there are about 350 types of sharks that live today. Only  about 30 different sharks can attack people. The biggest shark is the whale shark. It is 60 feet long  and it weighs 15 tons. The whale  shark does not attack people, and the whale shark  lays  the world's  biggest eggs.  It is 12 inches long . The whale shark has thick skin which is 8 in thick.  It  swims slow; it's  lazy; and it eats small fish and plankton.