This American Life just did a segment where the experts were very skeptical of both the theories presented in this article - that the first encounters near Spain were caused by a traumatic event of a matriarch, and also that orca pods would communicate with each other to spread the behavior. The theory presented in that segment was the first orcas are sort of like rowdy teenagers participating in a fad, and the newer…
Edit: ok Ira was sick and it's mentioned halfway through