Killer whales near Spain have sunk 3 sailboats. A lonely orca named Luna who got separated from his family 20 years ago also damaged boats — but scientists say he just wanted to play.

• Killer whales near Spain and Portugal have sunk three sailboats in recent years.
• An orca name Luna that was damaging boats near Vancouver Island in the 2000s just wanted to play.
• Luna lived alone and befriended humans for years before he was struck and killed by a tugboat.

A string of incidents in which killer whales have rammed into and sunk sailboats may have been triggered by a single, traumatized female, one scientist said — but at least one other orca has previously been documented purposefully colliding into boats, and for much less nefarious reasons.

A population of killer whales near Portugal and Spain's Iberian Peninsula first began having "disruptive" interactions with boats in 2020. Since then, researchers have identified hundreds of incidents in which an orca approached or collided with boat, though most incidents were short and caused minimal damage. The behavior generally follows the same pattern, with the orca approaching the back of the ship and hitting the rudder until successfully causing the boat to stop.

In three cases, the orcas have caused sailboats to sink, leading some to brand the interactions as "attacks." Alfredo López Fernandez, a biologist at the University of Aveiro in Portugal who is studying the orcas, told LiveScience the behavior may stem from a single female named White Gladis who was struck by a boat and has since taken to ramming them. The other orcas may simply be learning the behavior from her.

Andrew Trites, director of the Marine Mammal Research Unit at the University of British Columbia in Canada, told Insider he was "blown away" by the recent incidents, adding they were "unprecedented." However, the encounters reminded him of a young male orca named Luna that engaged in similar behavior with boats around 20 years ago.

Luna was part of the L-pod of the Southern Resident Community of orcas, which are endangered. The L-pod today is made up of about 30 individual orcas, who spend their summers near Washington's San Juan Islands. They eat fish, primarily salmon, and spend the winters hunting along the Pacific Coast, from California to Alaska.

But in the summer of 2001, two-year-old Luna somehow ended up all alone.

"He got lost and separated from his pod, and was left behind in one of the outer coastal areas of British Colombia," Trites said.

After Luna turned up solo in the Nootka Sound of Vancouver Island, scientists were initially skeptical of reports that a baby killer whale was all alone. Considering Luna's age and the social nature of orcas, they also weren't sure he would survive. But somehow he did, managing to hunt and feed himself without the support of a pod.

"Being a social animal, he got very lonely and became quite attached to boats," Trites said. "He learned how to swim up behind a boat, grab onto the rudder, and dismantle it to stop the boat from moving. It was an animal that was clearly searching for social interaction."

Luna's desire to play with boats and be near humans made him famous. He would swim up to boats and rub up against them, or vocalize at people and even let them pet him. While many adored the playful killer whale who befriended humans, the situation inevitably caused problems.

News reports from the time recount how Luna's behavior damaged several boats. In 2004, the 75-year-old skipper of a fishing boat told the Seattle Post-Intelligencer that after Luna damaged the boat, forcing him to rig a rope-and-pulley system just to steer, the orca continued to "harass and bang around the boat like a beach ball for five hours."

The interactions prompted efforts to remove Luna and reunite him with his pod, but those were opposed by a local Native community. Shortly before Luna appeared in Nootka Sound, the chief of the Mowachaht/Muchalaht First Nations had died. The Mowachat/Muchalahat peoples believed Luna embodied the spirit of their chief and did not want the orca to be moved.

Luna remained in the sound for nearly five years, but "unfortunately for Luna, it did not end well," Trites said.

The orca was killed in 2005 after being struck by a tugboat.

The killer whales 'attacking' boats might just be playing

Like in the case of Luna, Trites believes the whales near the Iberian Peninsula are more likely engaging in playful behavior with boats, rather than "attacking" them.

"They're very tactile. They have a sense of touch. Their skin is sensitive," Trites said of orcas, explaining that they are known to rake their teeth over the body of another killer whale, rub and bump into each other, and even rub their bodies up against pebbles.

Unlike Luna, this situation is unique in that it involves a growing number of whales. Trites said orcas are extremely intelligent and could learn behaviors simply by watching. The fact that other orcas are mimicking and adopting this behavior suggests it is being positively reinforced, meaning they are gaining some benefit or pleasure from it.

He also said the idea that a single killer whale was traumatized and is taking "revenge" with the help of other orcas felt a bit too "Hollywood movie."

"Undoubtedly the people on board these little boats feel attacked," Trites said, but noted he did not think "attack" was an accurate term as the intent of the behavior is not yet clear.

Still, he said these interactions can be disastrous for whales and humans. And if more and more killer whales in this population continue to adopt the behavior, it may only be a matter of time before a whale, or a person, is seriously injured or killed.