The Mysterious Rise of Orca Attacks on Boats.

An orca attacked a yacht off the Shetland Islands in Scotland, marking the first incident in the northern seas. The retired Dutch physicist on board said the mammal repeatedly rammed the stern of the boat, creating "soft shocks" through the aluminum hull. The incident follows a series of aggressive orca behavior near Spain and Portugal, where the mammals have touched, pushed, and even turned vessels. Experts say the orcas could be teaching each other to adapt this behavior, but there has never been a documented case of an orca attacking and killing a human being.