As we've posted, orcas have recently been attacking boats in Portugese and Spanish waters. Last week though, an orca rammed a yacht off the Scottish coast, more than 2,000 miles from the previous incidents.
The behavior appears to be spreading through social learning, with orcas imitating each other and reproducing acts they deem advantageous or interesting in some way, Alfredo López Fernandez, a biologist and representative of the Grupo de Trabajo Orca Atlántica, or Atlantic Orca Working Group (GTOA), previously told Live Science[…]
"It's possible that this 'fad' is leapfrogging through the various pods/communities," Conor Ryan, a scientific adviser to the Hebridean Whale and Dolphin Trust, told The Guardian. (A fad is a behavior initiated by one or two individuals, which others adopt through social learning and then abandon.)
Although 2,000 miles (3,200 kilometers) separate orcas in the North Sea from the Iberian population, there might be "highly mobile pods that could transmit this behavior a long distance," Ryan said.
Experts with the GTOA suspect the attacks are linked to human activities at sea. Fishing, noise pollution and boat traffic, "even in an indirect way, are the origin of this behavior," López Fernandez told The Guardian.