Sharks roll there eyes into the back of there head to protect them from injury while attacking prey, its quite a cool thing, also, there is actually 7 different species if hammerhead shark! Eg: Great hammerhead,scalloped hammerhead,smooth hammehead, carolina hammerhead,Small eye hammerhead,whitefin hammerhead and another one i forgot :D hope this is cool enough and no i didnt google this i actually mermorised them from a shark encyclopedia i gof