Have you ever heard the saying "if there are dolphins around then you don't have to worry about sharks"? Is this true? It is believed by some that sharks fear dolphins, but why?
Sharks in fact do attack dolphins from above, behind and below to prevent being detected by the dolphins echolocation. It is unlikely that a shark will not attack simply because there is a dolphin in the area. In fact it is not necessarily whether sharks fear dolphins, but rather whether dolphins are fearless of sharks. A battle between a shark and dolphin often pits brawn against brains. Research shows that many dolphins actually survive shark attacks by using everything from karate-type moves to ganging up.
Depending on the species of shark and geography will determine whether they prey on dolphins. Quite often a shark will prey on smaller more vulnerable marine mammals such as calves. This seems pretty logical, pick on the smaller guy. While we know sharks and dolphins do interact there is not much first hand observation and therefore more research is needed.
Due to there being the possibility of a shark preying on a dolphin, it is not always the case that if there is a dolphin around whilst your surfing there will be no shark. A group of dolphins on the other hand, may be intimidating to a single shark. The truth to this saying will depend on a lot of factors, however, due to what we know about their interaction, just because their is a dolphin nearby does not mean there are no sharks.