Revenge of the killer whales? Recent boat attacks might be driven by trauma

Scientists and sailors say orcas, also known as killer whales, are stepping up "attacks" on yachts along Europe's Iberian coast, with one skipper who's been pursued by the marine mammals on two separate occasions suggesting that their tactics are becoming more stealthy.

Delivery skipper Dan Kriz, who had to be towed into port after orcas destroyed the rudder on a boat he was on in 2020, had an almost identical experience in April.

"My first reaction was, 'Please! Not again,'" Kriz told Newsweek.

Unlike last time, the orcas made a stealthier approach without the characteristic squeaks they normally use to communicate, he says. They made quick work of the two rudders on the catamaran Kriz was delivering. "Looks like they knew exactly what they are doing. They didn't touch anything else," he said.

Most marine scientists have characterized hundreds of encounters between boats and orcas that have sunk at least three vessels and damaged dozens of others over the years as a "fad," implying that the animals will eventually lose interest and resort to more typical behavior.

But if that's the case, there are few signs this behavior is going out of style anytime soon. According to a June 2022 study published in the journal Marine Mammal Science, orcas have stepped up the frequency of their interactions with sailing vessels in and around the Strait of Gibraltar, the busy waterway that links the Mediterranean Sea with the Atlantic Ocean.

Some researchers think it's merely playful behavior

As NPR first reported last August, many scientists who study orca behavior believe these incidents — in which often one or more of the marine mammals knock off large chunks of a sailboat's rudder — are not meant as attacks, but merely represent playful behavior.

One hypothesis put forward by Renaud de Stephanis, president and coordinator at CIRCE Conservación Information and Research, a research group based in Spain, is that orcas like the feel of a boat's rudder.

"What we think is that they're asking to have the propeller in the face," de Stephanis told NPR last year. "So, when they encounter a sailboat that isn't running its engine, they get kind of frustrated and that's why they break the rudder."

In another recent encounter, Werner Schaufelberger told the German publication Yacht that his vessel, Champagne, was approached by "two smaller and one larger orca" off Gibraltar.

"The little ones shook the rudder at the back while the big one repeatedly backed up and rammed the ship with full force from the side," he said.

The Spanish coast guard rescued Schaufelberger and his crew, towing Champagne to the Spanish port of Barbate, but the vessel sank before reaching safety.

The encounters could be a response to past trauma

Since 2020, there have been more than 500 encounters between yachts and orcas in the area, according to one of the study's co-authors, Alfredo López Fernandez, a biologist at the University of Aveiro in Portugal and a representative of the Grupo de Trabajo Orca Atlántica, or Atlantic Orca Working Group.

López Fernandez believes that a female known as White Gladis, who leads the group of around 40 animals, may have had a traumatizing encounter with a boat or a fishing net. In an act of revenge, she is teaching her pod-mates how to carry out revenge attacks with her encouragement, researchers believe.

"The orcas are doing this on purpose, of course, we don't know the origin or the motivation, but defensive behavior based on trauma, as the origin of all this, gains more strength for us every day," López Fernandez told Live Science.

It's an intriguing possibility, says Monika Wieland Shields, director of the Orca Behavior Institute.

"I definitely think orcas are capable of complex emotions like revenge," she says. "I don't think we can completely rule it out."

However, Shields is not ready to sign on to the "revenge" hypothesis just yet. She says that despite humans having "given a lot of opportunities for orcas to respond to us in an aggressive manner," there are no other examples of them doing so.

Deborah Giles, the science and research director at Wild Orca, a conservation group based in Washington state, is also skeptical of the hypothesis. She points out that killer whale populations in waters off Washington "were highly targeted" in the past as a source for aquariums. She says seal bombs, small charges that fishers throw into the water in an effort to scare sea lions away from their nets, were dropped in their path while helicopters and boats herded them into coves.

"The pod never attacked boats after that," she says. "It just doesn't ring true to me."

Shields says it's important to remember that whatever the motive is for the behavior of the orcas off the Iberian coast, it isn't being transmitted to pods in other parts of the world.

"We've had folks here in Washington [asking] 'is it safe to go out in the water here with these orcas?'" she says. "While this is kind of an ongoing situation in that specific place, I don't think there's any reason to think it's going to start spreading to other populations of orcas."

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