A pod of orcas have sunk a yacht in the Strait of Gibraltar

For 45 minutes, the crew of the Grazie Mamma felt like they were under attack from below. A pod of orcas had zeroed in on the yacht's rudder as it made its way through the Strait of Gibraltar last week, and rammed it repeatedly, "causing major damage and leakage," according to the company that operated the boat.

Rescuers were able to save the crew and return them safely to port in Tanger-Med on the coast of Morocco. Their vessel, though, sank into the sea.

"This yacht was the most wonderful thing in maritime sailing for all of us," read a statement posted to Facebook by Morskie Mile, the Warsaw-based touring company that operated the boat. "Very good memories will be transferred to Grazie Mamma II. Love of the sea always wins and friendships remain with us."

The company said it is working to ensure its upcoming trips to the Canary Islands go on without a hitch.

Last week's incident was the latest in a string of recent "attacks" by orcas in the waters separating southern Europe and northern Africa — encounters that have left researchers scratching their heads.

Since 2020, there have been about 500 encounters between orcas and boats, Alfredo López Fernandez, a coauthor of a 2022 study in the journal Marine Mammal Science, told NPR earlier this year. At least three boats have sunk, though there is no record of an orca killing a human in the wild.

Scientists have been trying to pinpoint the cause of the behavior.

One theory among researchers is they're just playing around. Other researchers say it may be that the whales like the feel of the rudder.

"What we think is that they're asking to have the propeller in the face," said Renaud de Stephanis, president and coordinator at CIRCE Conservación Information and Research in Spain, in an interview with NPR last year. When they encounter a sailboat without its engine on, "they get kind of frustrated and that's why they break the rudder," de Stephanis said.

Another theory is that the behavior may be some sort of act of revenge due to possibly traumatic, previous encounters with fishing boats.

"I definitely think orcas are capable of complex emotions like revenge," Monika Wieland Shields, director of the Orca Behavior Institute previously told NPR. Shields said she does not think "we can completely rule it out," even if she was not entirely convinced herself.

Deborah Giles, the science and research director at conservation group Wild Orca, says pods in other areas, such as near Washington state, have been targeted by humans, but haven't shown a pattern of ramming boats.

Which underscores why researchers say it's difficult to draw any conclusions from the interactions documented to date. In an open letter published this summer, 30 scientists cautioned against "projecting narratives onto these animals," writing that "In the absence of further evidence, people should not assume they understand the animals' motivations."

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