The most common myth is that great whites, with their poor vision, attack divers and surfers in wet suits, mistaking them for pinnipeds (seals and sea lions), their main prey. In this scenario, once the animal realizes its mistake, it releases the victim and swims away.
"Completely false," said R. Aidan Martin, director of ReefQuest Centre for Shark Research in Vancouver, Canada. A shark's behavior while hunting a pinniped differs markedly from its demeanor as it approaches people—suggesting that the animal does not confuse surfers for seals.
Sharks do not attack humans for the sole purpose of hunger. In fact, sharks do not know what the feeling of hunger is, and in fact, can go for many months without eating. This is not to say that sharks do not attack with the intention of seeking prey. Many attacks on divers and surfers especially can be attained to searching for food. To a shark, a surfer on a surfboard slightly resembles that of a seal or sea lion, or a diver in a black wetsuit can look like other prey.
Sharks also attack humans because they have been provoked or agitated by the person. Many spear-fishers have been attacked by reef sharks because when they spear fish, the blood from the fish and it's vibrations can sometimes result in a feeding frenzy by many sharks. Bright colours can also be counted for attacks.
As many people have believed in the past, sharks do in fact can see colours, and do indeed have very good eyesight. Avoid wearing the colours of orange and yellow, as this can aggravate the shark, and possibly lead to attacks. Sharks are in fact attracted by splashing and vibrations in the water, and it can sometimes be attributed to attacks. Most scientists have not been able to predict why and where sharks attacks. Read more: wiki.answers.com...
