Are the orca "attacks" spreading? What cultural evolution teaches us about fads in animals

The killer whale on boat "violence" doesn't seem to be going away. Last week, an orca (Orcinus orca) reportedly launched itself into a yacht off the coast of the North Sea. The event, which wasn't independently verified by Salon, is the first time a killer whale incident has been known to happen off the coast of Scotland, and nearly 2,000 miles from where the behavior has been reported hundreds of times off the coast of Spain and Portugal.

Dr. Wim Rutten, a retired Dutch scientist, told the Guardian he was fishing when an orca suddenly appeared and started ramming itself into his boat. According to the report, the killer whale hit the boat multiple times. "What I felt [was] most frightening was the very loud breathing of the animal," Rutten told the Guardian. "Then he disappeared ... but came back at fast speed, twice or thrice ... and circled a bit."

It raises a series of intriguing questions: Are orca attacks spreading? Will they become more common? And why are they doing this anyway?

The event adds to a running list of incidents where orcas have caused damage to, or had physical interactions, with boats. The news first made headlines when LiveScience published an article on May 18, 2023, suggesting that orcas might be teaching each other how to sink yachts. Since 2020, out of 500 recorded interactions, there have been three sunken ships. According to the report, orcas appeared to follow a "clear pattern" of behavior where an orca approaches the stern of a ship, strikes the rudder, then loses interest when the boat stops moving. One researcher theorized that a female orca, called White Gladis, could have had a traumatic collision with a boat and is suspected to have started the "trend" of orcas having physical contact with other boats.

The altercations have turned the orca into a personified meme on the internet, including being "blamed" for sinking the Titanic-seeking sub that imploded last week. (There is no evidence anything sunk the Titan submersible aside from shoddy engineering.) As Salon previously reported, the behavior is likely yet another account of orcas developing a peculiar fad — which both orcas and other animal species have a history of doing. However, in this case, it's one that could do more harm than good. The latest reported incident could be evidence that this behavior is here to stay, and that it's spreading to other orca pods thanks to cultural evolution.

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Cultural evolution is distinct from genetic evolution in that it involves abstract behaviors that are passed down to offspring, rather than utilizing DNA or RNA. Tool use among chimpanzees is a prominent example.

"We usually think of learned behaviors as being adaptive and having some utility but they certainly don't have to, and we should know that as humans, all kinds of things get started," Lance Barrett-Lennard, PhD, senior research scientist at the Raincoast Conservation Foundation, told Salon. "Once you've got a predisposition, the machinery, the brain, the instinct to learn from one another, then maladaptive behavior can be learned as well and sometimes spread for a while. We call these cultural traps — in humans, cigarette smoking is a good example."

A "cultural trap," Barrett-Lennard said, happens when a behavior spreads through a population despite being maladaptive. It doesn't improve survival, reproduction or biological fitness. At this point, he said he wouldn't categorize the behavior from the orcas as a cultural trap because they aren't being injured or targeted by boat owners. At least, not yet.

"This is a kind of cultural revolution. In the short timespan, sometimes this kind of behavior, if it's directly related to food or some survival value, it may very well fade away fairly quickly," Barrett-Lennard said, "We'll see whether that happens or not."

Barrett-Lennard said he would compare this behavior to what we've seen in other populations — like bottlenose dolphins.

"In Australia, some years ago, they [dolphins] started carrying sea sponges around on their noses," he said. "And this behavior had never been seen before by people studying these particular populations for quite a long time. Then suddenly, they saw it a few times and then it would seem to [disappear], it seemed to be a bit of a fad — but it spread very quickly through the population."

Andrew Whiten, an evolutionary and developmental psychologist at the University of St. Andrews, explained in a paper published in the journal Science that it's well-established that animal behaviors that can be passed from one individual in a group to another individual, a chain that can be passed down to generations. However, up until the mid-20th century, culture was thought to be an exclusively human phenomenon.

"The revelation that cultural inheritance permeates many species' lives is increasingly recognized to have profound implications for evolutionary biology at large, because it provides a second form of inheritance that builds on the primary genetic inheritance system, facilitating cultural evolution," Whiten wrote. "The two inheritance systems may generate rich interactive effects, as they have in humans."

One example Whiten pointed to was how humpback whales learned to slap the sea surface with their tails, a trick known as "lobtail feeding." Then, they will blow bubbles around their prey to confuse them. While so-called "bubble feeding" was already known for decades, lobtail feeding was first recognized in 1980, spreading over two decades and creating a new hunting tradition for hundreds of other humpbacks.

However, it's likely too soon to know if the orca behavior is spreading or if it's more than a fad. Barrett-Lennard said the behavior off the coast of Scotland could be connected to what's been happening on the Iberian peninsula, but scientists don't know right now. He said it's possible that they were the same whales because they have the ability to travel that far, but so far, nothing is definitive.

"We're always struggling to learn how these populations of killer whales around the world are connected to each other," he said. "We usually use genetics to see how closely related they are."

But some scientists are remaining skeptical about the most recent incident. Monika Wieland, director of the Orca Behavior Institute, told Salon via email she believes it's "extremely unlikely these events are connected."

"Without any videos of the encounter, or evidence of damage on the vessel, I suspect that the incident off the Scottish coast may have been sensationalized a bit," Wieland said. "With all the media coverage the Iberian orcas have been getting, I think we've pre-conditioned people on how to interpret any orca approaching a vessel."