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What's behind the increase in orca-human interactions, boat attacks? Here's what an expert thinks

The number of interactions between killer whales and humans has increased alarmingly in recent years.

Videos circulating the internet show the large marine mammals swimming around sailing boats or medium-sized vessels, pushing and even turning them, sometimes resulting in damaged rudders and sunk ships.

This behaviour, called disruptive, was first noted in 2020. Since then, there’s been a remarkable 298 per cent increase in the frequency of encounters from 2020 to 2022, as reported by the Atlantic Orca Working Group (GTOA), a group of Spanish and Portuguese marine scientists formed to understand the new behaviour.

The GTOA reported 52 interactions between July and November 2020 in the waters of the Strait of Gibraltar and Galicia (NW Peninsula), including the coast of Portugal. The new behaviour reached 197 interactions in 2021, and 207 were recorded in 2022.

The interactions have raised important questions about the dynamics between these majestic marine creatures and our own species.

Are killer whales rising up against humankind? A cetacean expert doesn’t think so.

On Monday, talked to Thomas Doniol-Valcroze, head of the Cetacean Research Program at Fisheries and Oceans Canada in Nanaimo, B.C., to explain the reasons behind the increase in interactions, explore the types of encounters, and examine the implications for both humans and killer whales.


GTOA found 21 different cases of historical records of interactions between orcas and humans, from the attack on the shipwrecked whaler Essex in 1820 to several incidents in Vancouver between 2003 and 2018, and even an attack suffered by a surfer.

While there is no doubt these interactions have suddenly increased in the last three years, Doniol-Valcroze said this behaviour has not been explained yet.

“There’s not really any consensus. There’s just an array of different hypotheses,” he told

The theories range from the orcas being stressed, teaching each other this “self-defence” technique, to just that they are being playful, said the B.C. scientist.

“I'm more willing to think this is something to do about play. I mean, after all, those animals are big dolphins, and they're certainly interested in boats,” he said. “They are curious animals.”

Doniol-Valcroze said he thinks these kinds of interactions will not stop anytime soon.

“If it is really a game, and if they find it fun, they just do it more and more.”

He also added it would be interesting to see if these disruptive behaviours will become less frequent as the young individuals grow or if they will teach this to new generations.

While these are still somewhat harmless interactions, “you wouldn't want this behaviour to spread in the population, but it has the potential to do so.”


The cultural transmission of behaviours in orcas can be transmitted from one group of killers to another, explained Doniol-Valcroze.

In British Columbia, there are various populations, like the northern and southern residents, which hunt fish, and there are also the Bigg’s killer whales, called transient killer whales, which hunt other marine mammals.

“There's behaviour we've seen being transmitted from one group to another, but we haven't seen that happen across populations,” said the B.C. scientist explaining populations between orcas in Canada and those in Europe do not interact with each other, making the transmission of behaviour unlikely.


The videos show a few individual whales, mostly juvenile, of the Iberian orca population – a unique subpopulation of orcas that lives in the northeast Atlantic. In these episodes, animals intentionally approach the boats and focus on the submerged moving parts, like the rudder.

“They are still wild animals, and they're really big and strong, so it doesn't take much for them to break a sailboat,” said the cetacean expert.

Doniol-Valcroze said the behaviours shown in the Spain and Portugal interactions are not the orcas’ regular signs of hunting: fast speed, water splashing, co-ordinated communication, etc.

In the videos, “they’re fairly calm, they don’t seem agitated, and they are certainly not going after the humans in the boat,” he said.

He added he has had similar interactions when researching B.C. where killer whales, belugas and dolphins will follow the research boats and put their heads right behind the propellers.

“It’s kind of unnerving because you wouldn't want these animals to be hurt. But they seem to enjoy the feeling of the propeller and the flow of the water and the bubbles on them, and that's quite widespread,” he said.

“It feels, to me, like these whales are going to sailboats, and maybe they see the propeller is not turning, and they want to play with things and try to get things in motion.”


While there is no reason for people to be afraid, Doniol-Valcroze said the best thing to do is to keep a distance from the animal.

“Maintain your course and your speed, basically not doing any sudden changes,” he said.

He also added a good rule of thumb is to remember these are wild animals protected by law and shouldn’t be harassed or bothered by humans.

“It’s best to just not try to interfere with anything they're doing like socializing or hunting for their prey,” he said. Top Stories

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