See all Science Weekly transcripts on Applepodcasts

This is The Guardian.

Are you hashtag Team Orca or Team Yacht? Social media users around the world are picking sides in a growing fight between killer whales and sailors. Stories and videos of orcas slamming into boats, biting rudders and sometimes even sinking vessels off the coast of Spain and Portugal have gone viral.

A group of orcas severely damaged a yacht off the coast of southern Spain. The pod broke the rudder and pierced the hull of the boat in the early hours.

Then last week, a Dutch sailor off the coast of Shetland had his yacht rammed, causing speculation that the behavior is traveling north. 1 theory is that the killer whales may be finally organizing to exact their revenge.

Oh, Right here. They're coming for the rider. He's going for it. Oh my god. That's a big 1.

And while you couldn't blame the animal world for wanting to rise up against us humans, is that really what the orcas are up to? What are these encounters about? And are they spreading? From the Guardian, I'm Madeline Finlay and this is Science Weekly. Hannah Strager, you're a biologist, a whale researcher and author of the book The Killer Whale Journals, Our Love and Fear of Orcas.

And you've been following the story of these orca attacks. So first of all, tell me, if a boat was in an area with orcas, Is this a behaviour you might usually see or do orcas typically avoid boats or do they come into contact without it being an attack?

It would be normal for them to be quite curious. I mean, often they just pass by and they are busy with something else. But every now and then they will be curious. They'll come swim around the boat. Maybe even 1 of them will stick the head up, what we call a spy hop.

Sometimes they'll swim under the boat and you can admire their black and white colouration from the railing. But for them to actually ram boats or bite the rudders is completely extraordinary. It is not something that has ever really happened before or happens anywhere else in the world.

So when did people first start to report something a bit different happening off the coast of Spain and Portugal?

In 2020. I think it's agreed that the first animals that did this were some young animals. And since then it has spread. So now quite a few of the animals in the population is doing it. I think it's important to stress that the population of killer whales around Portugal and Spain is very small.

It's a population of killer whales which is probably less than 50 individuals and many of these are known individually. They have names and numbers so that the researchers in the areas can identify them. In the beginning it was just a few of them and now approximately at least 15 individuals has been seen engaged in this behaviour.

So it's a small population, but are they all from the same pod of orcas?

They are from the same population, from the same group. They're probably all related to some degree and some of these travel together in smaller groups or parts or families. You'll normally not see all 30 or 40 of them together. The typical thing is to see 567 animals together.

So this started back in 2020, but how many attacks have there been and can you describe exactly what these encounters are like?

Yes, I can. I haven't experienced it myself, but I've spoken to quite a few who has had quite frightening experience. 1 was, he was a skipper on a Norwegian vessel. He was traveling with his family. They've heard of this, so they were kind of looking out.

And he had just come up on deck. He was looking around, it was a beautiful day and suddenly he saw a fin and so he braced himself. He was thinking, wow, is this happening to us now? And they had 3 or 4 individuals diving under the boat where the keel is and the rudder is. So they were going for the rudder and they could feel that the killer whales were actually gripping the rudder with their mouth, with their teeth and shaking it.

They couldn't hold on to their steering wheel. It would snap out of their hands every time the killer whales below the water would push it very hard or bite it. And this continued, I think, for more than an hour and an hour and a half. And in the end, they had to call the Spanish Coast Guard and ask for assistance because they lost the ability to maneuver. So that's a rather typical encounter.

And there's been about

500

of those since it started in 220 so it's not a small problem. It's actually quite a big problem.

I Mean it's quite a lot. It sounds like the orcas are doing this quite regularly. And obviously, no 1 can ask them why they're doing it. But what are the possible reasons why the orcas are behaving like this?

I can give you 3 possible reasons that I think we can't rule out that this is the case. But I think it's important to stress that we may never find out. And there's not really a way that's easy to test it. But if I summarize the 3 theories, the 1 is that this is like a reaction to living in a stressful environment. There's a lot of boat traffic in the area.

There's a lot of ship noise. There's a lot of high levels of pollution in the area. And also these killer whales actually have high levels of different pollutants in their tissue. So 1 theory that all these stress factors combined into making this odd reaction. Then there's the theory that is this some kind of revenge?

Have someone or many or several animals had an encounter with a boat, a sailing vessel perhaps, which was fatal or where an animal was hurt? And are they now, have they turned their anger towards sailing vessels in general? It is true that some of the animals that have been observed doing this behavior actually have some scars and some wounds that could have been inflicted from a boat. We can't say if this has happened after they started this behavior, because obviously the behavior is also very risky for themselves. I mean, they get in contact with the boats, they come close to the propeller.

And the third hypothesis is this is actually just some kind of play. Although of course it's not, it doesn't feel like play for the people involved in it. Still, for the whales it may just be fun. They have for some reason developed this habit and it has spread in the population and now they are doing it. It maybe it empowers them.

They feel they can turn a boat away, they can bite the rudder. So I think it would be fair to ask now, but do killer whales play? Is this a common thing for them to do? And it is. It is quite common for them both to be attracted to boats, but also to play around with different things.

They've been observed playing with kelp. They've been observed playing with salmon that they place on their head for no obvious reason. I have seen them play around with jellyfish, swimming with jellyfish on their snout. They don't eat deer or fish, so they're probably doing this as some kind of balancing act. So they are quite inquisitive, they are quite playful, and I certainly can't rule out that it is a play behaviour.

Obviously on social media everyone is enjoying the idea that this could be revenge. But have you spoken to anyone who's experienced an attack about what they thought was going on?

I spoke to a crew member who was on board a French vessel that sunk November 1st. He was a biologist and therefore also quite used to observing animals. And It was his feeling that it was play. And when the boat started sinking, the whales completely lost interest in the boat. So by the time that this crew had to go into the life raft, the whales had already left.

They're not interested in the people and they were also not interested in the boat when it was sinking. And this is not a proof that it's play. But if you ask me, as someone who has looked into a lot of the interactions between people and killer whales, and which is actually what my book is about. I would say that there's been many, many cases in the world where it would have been not unlikely that killer whales have reacted with a revenge motive or aggression if they were inclined to do so. They have been hunted in Iceland and Norway because they've been seen as a competitor to the herring fishery and they've been shot at.

And still there's been no reaction from any of the killer whales.

Orcas do have a history of interacting with boats and you know if this is young orcas having fun and playing It might just be they're going through their boat phase. But do you think this is significant?

Yeah, I think it is significant. And had you asked me 4 years ago if some local population of killer whales somewhere in the world would sort of start attacking boats and sinking them, I would have said, out of the question. So it is extraordinary, and it is significant. But what it signifies, don't ask me. I don't know.

And nobody really does. I think you just have to accept that these large animals are living their life and they they've started having this odd behavior and at the moment the best we can do is listen to the advice of trying not to be interesting to them and then hopefully it will stop because really the huge problem right now is is not just the boats which I acknowledge represents a lot of value for the people who have them, but that's also a threat to the killer whales because a lot of boat owners and crew members are very scared and they take different tools in their hands to try to avoid it. I've heard of people who pour diesel in the water, who pour chlorine in the water on top of the heads of these animals, who throw firecrackers in the water and even dynamite. So the behaviour is actually also jeopardising the conservation of this really highly endangered group of killer whales.

And last week it was reported that an orca had exhibited this same behaviour towards a boat off the Shetland Islands, leading people to speculate that the behaviour is spreading. What do you make of that?

There has been a very recent report from the Settler Islands of a sailor, a Dutch sailor, who had 1 animal come up to the aft of his sailing vessel. And he reported that the animal was pushing the hull or ramming the hull a few times and he was scared obviously and the animal very quickly lost interest in the boat again and disappeared. And there was no biting of the rudder. I don't know what to make of this observation. So far it's 1 incident with 1 animal.

And we cannot rule out that killer whales from the British Isles have been swimming in the area with Iberian killer whales and sort of picked up this behavior from them. We don't know how far the British Isle killer whales usually go. They have been seen in Iceland, so we know they can travel far. So that cannot be ruled out. But it's also possible that this is just a single incident and it's not possible to say if this behaviour is spreading, not yet.

Now whether or not this is spreading beyond the Iberian Peninsula, the behaviour has spread throughout that population and they've learned from 1 another. So I'd like to dig into this a little more. You've spent a large part of your career researching these creatures. So how have they been shown before to do this, to teach each other things?

Well, they teach each other many things and they are quite quick learners. For instance, their whole vocal repertoire is something that they learn from the family that they are in. Kiloelves in a family group have their own, at least in Norway and in Canada, where they've been studied very intensely, have each group have their own repertoire of sounds and those sounds are learned by the young killer whales as they grow up. So that's 1 way that they are learning behavior. Another way that they're learning behavior is their hunting methods which are also very coordinated and includes a lot of skill.

The killer whales that I know best are the ones in Norwegian waters and they are primarily herring eaters. So a whole group will swim around a school of herring and the young ones will learn how to do this. They'll learn how to turn the flesh, their white sides, their white bellies, towards the herring to scare them into a tighter and tighter group. They'll exhale underwater, creating large columns of bubbles that further scares the fish into a tight ball of fish. And finally, in the end, they swim into this tight ball of fish and they whack them with their tails.

And all these things a young killer whale will have to learn in order to become a successful herring hunter herself.

And Hannah, you've described some of the encounters between these killer whales and the people on the boats. But of course, you've had lots of contact with orcas as well. So, perhaps you can describe to me what it's like to come face to face with 1 of these creatures.

Well, it's a... For me, for sure, it's pure joy. They are so incredibly beautiful. No designer could have made them more spectacular in their black and white. They are incredibly interesting, I think, because they are doing things.

They are, it's a social group you're looking at. There's always a lot going on. And I think what makes it interesting is that you're looking at social relations between animals which are incredibly different from us. But when we see them at the surface, when we see a killer whale mom swimming with her little young ones, When we see them playing, we see them jumping out of the water, or we also see behaviors that we kind of recognize. We recognize this caregiving behavior, we recognize playful behavior.

We realize that they are just like us in many ways. And I think that's part of their attraction is that they're not so far, despite the way they live. And that is part of why they are really attractive.

Well, it's been absolutely fascinating to get a glimpse into the orcas' world. Thank you so much.

Oh, it was a pleasure.

Thanks again to Hannah Strega. You can find more coverage of the Orca encounters at theguardian.com. And that's it for today. The producer was me, Madeline Finlay, the sound design was by Tony Onochukwu, and the executive producer was Ellie Burey. We'll be back on Thursday.

See you then.

This is The Guardian.