Orcas sank three boats off the coast of Portugal, but don’t call them “killer” yet

Three recent incidents of killer whales appearing to attack and sink boats off the southwestern tip of Europe are under scrutiny to find out if the animals deliberately invaded ships and if they are learning the behavior aggressive towards each other.

Encounters between orcas, or killer whales, and boats have increased since 2020, although no human injuries or deaths have been reported. In most cases, the whales did not sink the boats.

The spate of incidents since 2020 has prompted a scientist in Portugal to say the attacks could indicate that the whales intend to cause damage to sailboats. Others, however, are more skeptical, stating that while the behavior may be coordinated, it is not necessarily coordinated aggression.

“I think it’s considered aggression because it causes harm, but I don’t think we can say the motivation is necessarily aggressive,” said Monika Wieland Shields, director of the Orca Behavior Institute, a nonprofit research organization based in Washington State. .

At least 15 interactions between killer whales and boats off the coast of Iberia have been reported in 2020, according to a study published last June in the journal Marine Mammal Science.

In November 2020, the National Maritime Authority of Portugal issued a statement alerting mariners to the “curious behavior” of juvenile killer whales. The statement said whales may be attracted to rudders and propellers and may try to approach boats.

Subsequent sinkings caused more concern.

The most recent encounter took place on May 4 off the coast of Spain. Three killer whales hit the rudder and side of a sailboat, eventually sinking it, as reported earlier this month in a German publication called Yacht.

A theory put forward by Alfredo López Fernandez, a biologist at the University of Aveiro in Portugal, has suggested that the assault started from a female killer whale who may have been hit by a boat – a traumatic experience that left him caused it to crash into sailboats. López Fernandez, co-author of the June 2022 study published in Marine Mammal Science, told Live Science that other orcas may have then adopted this behavior through social learning, which whales are known to to present.

But Shields said killer whales have not historically been known to be aggressive towards humans, even when hunted and held in captivity.

“They certainly had reason to engage in this kind of behavior,” she said. “There are places where they get shot at by fishermen, they saw family members taken into captivity in the 60s and 70s. And if anything were to motivate direct aggression, I would think something as it would have done.

Shields added that there were no clear examples of killer whales exhibiting what could be considered vengeful behavior against humans.

She said recent attacks on boats are likely more consistent with what is called “fashionable” behavior, which describes new but temporary behavior by a whale that can be imitated by others.

“It’s some kind of new behavior or game that a whale seems to invent, and it seems to spread throughout the population – sometimes for a few weeks or months, or in some cases for years – but in many cases it just walks away,” she said.

In the Pacific Northwest, for example, Shields and colleagues observed a fashionable behavior in southern resident killer whales that began carrying dead salmon on their heads for a period of time before the behavior escalated. suddenly stop.

Shields said the behavior of killer whales off the Iberian coast could also be temporary.

“It looks like the same kind of thing, where a whale played with a rudder and said, ‘Hey, that’s a fun game. Do you want to try it?’ And that’s the current fashion for this population of killer whales,” she said.

While Shields didn’t dismiss the trauma response theory out of hand, she said it would be difficult to confirm without more direct evidence.

“We know their brains are wired to have really complex emotions, so I think they might be capable of something like anger or revenge,” she said. “But again, it’s just not something that we’ve seen examples of, and we’ve given them many opportunities around the world to want to get back at us for various things. And they just choose not to. not do it.