Justin Gregg: when orca teach themselves to attack

In a so-called "orca uprising" killer whales have been attacking boats in Iberian waters, off Spain and Portugal,and are possibly teaching others to do the same. But why, and how will it all end? Dr Justin Gregg is a researcher with the Dolphin Communication Project, adjunct professor at St. Francis Xavier University in Nova Scotia and author of If Nietzsche Were a Narwhal.