Pretty neat video. Dolphins have long been known to protect humans in the water from sharks. They instinctively chase away sharks with high-pitched noises and general harassment. However, it must be noted, it is very unlikely that the cameraman was in danger. The hammerhead shark was likely just being curious and checking him out, as they usually do. Hammerheads rarely harm humans. We came across one in the Bahamas last summer and jumped into the water to see it! It was an amazing experience, although we scared the poor 10 foot hammerhead that swam away as fast as it could!