Quote Originally Posted by Vincent Butler View Post
A bull sperm whale is pretty much immune from killer whale attack, as they are very large and very aggressive towards orcas, though cows and calves are more susceptible. Orcas have been known to take down fin whales (the second largest whale), though they have not yet been known to take down a blue whale, at least not an adult, I don't know about juveniles. The thing is, the humpback is aggressive towards the orcas, whereas the fin whale does not take that approach.

Orcas are quite a bit larger than great white sharks, so no surprise about orcas dominating them.
As in the documented case of an orca attack on a great white off California, triggering the mass exodus of all the great whites in the region immediately diving deep and heading all the way to Hawaii before coming up again (one of the fleeing great whites had been electronically tagged previously, allowing researchers to keep track of where it was). That the great whites would en masse abandon their favourite feeding ground and only stop a couple of thousand miles away shows how this orca behaviour is recognised by the shark population. It also inspired research into how a single attack would provoke such a strong reaction from a widespread shark population.