Not one.
See SciAm: Orcas are more than one species, gene study shows
This reminds me of something I saw on television recently that showed Orca's had somehow learned that if they could launch a surprise attack on a Great White Shark and then hold it upside down for 15 minutes then they could have their way with it. It was amazing.
See DailyMailUK: Pictured: The moment a whale delivers a deadly 'karate chop' blow to a killer shark
