Dolphins are quite capable of fighting off sharks. In fact, orcas -- the largest dolphin species -- have been known to attack great white sharks. Dolphins use everything from a "karate chop" with their fins to ramming with their heads to fight off a shark attack.
Studies Point to a Variety of Fight Techniques
Via an investigation of scars and other signs, a team of U.S. and U.K. scientists looked at how dolphins living near The Bahamas defended themselves against mako and tiger sharks; the results were published in August 2014 in Marine Mammal Science. The researchers indicated to Discovery News that the sharks were least successful when they attacked the dolphins' dorsal fin and that the dolphins would often use a karate-chop technique to ward them off.
Orcas Attack Great Whites
Orcas are known to attack great white sharks. These big dolphins employ both the karate-chop technique and their massive teeth when going after sharks, according marine biologist Ingrid Visser, an orca expert. Visser said orcas use their tails to flip sharks upside-down -- rendering them immobile. The use of this technique suggests orcas may have a basic understanding of shark biology -- or at least how a shark behaves when rendered prone.