An orca started a fad in the summer of 1987 when it killed a salmon and returned to the surface with the dead fish draped on top of its head.
For a few pods of killer whales in the Puget Sound area of Washington state, wearing these "dead salmon hats" was "the cool thing to do for that entire summer," Monika Wieland-Shields, director of the Orca Behavior Institute, told ABC News. It was also one of the first examples of this type of trend-like behavior that humans witnessed spreading among killer whales.
More than three decades later, experts say that a spate of orca encounters with boats near the Iberian Peninsula in recent years could be another one of these orca social trends. What event may have triggered this behavior remains up for debate - one theory by some observers posits that a single orca was previously traumatized in an incident involving a boat, which triggered aggressive behavior that other killer whales have since learned to imitate.
At least 15 human-orca incidents were recorded in 2020, the year in which the encounters are believed to have begun, according to a study published in the journal Marine Mammal Science. Many of them included orcas biting or striking the rudders of sailboats. Three boats have sunk and dozens more have been damaged, according to tracking data from the Cruising Association. There have been no fatalities.
The encounters have spawned a blitz of alarming press and internet memes about a budding uprising of orcas supposedly enacting their revenge on humans. Meanwhile, some experts are calling for more nuance in how the public views these massive marine predators.
"There's something almost Robin Hood-like about thinking that we've pushed nature far enough that they're finally going to fight back. And people really seem to be getting behind that. There just isn't evidence that that's what's happening," Wieland-Shields said.
Wieland-Shields said she's not so sure the orcas are aiming to disable the boats, but they may be intrigued by the moving rudder mechanisms and trying to be playful with the push and pull as the captain tries to maintain steering control.
"We've done a lot of things to orcas around the world that could have easily inspired that type of revenge response. And never have we triggered that aggression from them toward humans," she said.
Dr. Lori Marino, a biopsychologist and expert on orca behavior, believes that humans often characterize orcas and other animals as one-dimensional beings when, in reality, they are far more complex.
"We think because we're human, we're the most intelligent, we're the most complex, we're the most sophisticated, and other animals are more like cartoon versions of themselves. But no, they are full beings with evolutionary histories, brains some of them bigger than ours and more complex," Marino told ABC News.
"Quite frankly, if they really wanted to take revenge, they would. You know, let's not fine coat it. If these orcas wanted to kill humans on those boats, they would. Period," Marino said.
Wieland-Shields also pushes back against this black-and-white view.
"Through the era of Free Willy and Shamu, orcas kind of morphed from killer whales into sea pandas. And now the pendulum is swinging in the other direction, where they're becoming the killer whales again," Wieland-Shields said.
But the truth lies "somewhere in between," Wieland-Shields said.
"This is one of the ocean's top predators. They deserve our respect, they deserve their space, but they aren't out to get humans, you know. We can coexist with them, we can observe them, and have awe at what they're doing, how they're behaving, without being afraid that our lives are at risk," Wieland-Shields said.