"Experts say the phenomenon may have started after a female killer whale had a traumatic encounter with a vessel at sea."
"A trio of orcas worked together to sink a yacht off the coast of Spain, the latest in a string of similar incidents involving the marine mammals and European boats.
The three killer whales, one larger than the other two, rammed into the yacht on May 4, skipper Werner Schaufelberger said in a media report published last week.
“The two little orcas observed the bigger one’s technique and, with a slight run-up, they too slammed into the boat,” he told Germany’s Yacht magazine.
The people aboard were all rescued, but the boat ultimately sank."