Apparently great white sharks show there fins above water when circling,does the same go for hamerhe

sharks are the consumate ambush predator. Almost every survivor of a shark attack all say the same thing. I never saw it before it attacked. I was a diver for many years, I interacted with leopard and blue sharks quite often. I was bitten one time, by a smaller blue shark on my left leg. At the time, I was feeding the sharks and was distracted for a moment. I didn't see a piece of bait that dropped down near my leg. The shark bit, and immediatley released my leg. I got away with 25 stitches and a new respect for even small sharks

As for hammerheads, they are bottom feeders as a general rule. They use those wide heads like a mine detector, but instead of regestering when the pass over metal, it picks up the electrical out put of small fish or crustacians just under the sandy bottom which they then grab and eat. There have been a few attacks credited to hammerheads on humans, but I don't know of any where they actually tried to eat a human. I think they mistook the flash of a foot or hand for a fish and bit out of instinct.