Your child can be a menace at the beach in this Child Hammerhead Shark Costume--or not. But any budding marine biologist will enjoy this!Did you know that there are over 470 different species of sharks? The smallest, the dwarf lantern shark, is less than seven inches long when fully grown. The biggest, the whale shark, can be up to 40 feet long; it is the biggest of all fish. (Yes, whales are bigger, but they aren't fish--they're mammals!) Hammerheads are in the middle of the shark range--the biggest ones are about 20 feet long.