The orcas are at it again: A pod of the black-and-white marine mammals sank a sailing yacht off the coast of Morocco in the Strait of Gibraltar last week. This marks the fourth vessel orcas have sunk in the region within the last two years, according to Live Science’s Harry Baker.
On the afternoon of October 31, orcas repeatedly rammed into the Grazie Mamma, a vessel owned by the Polish cruise company Morskie Mile, according to a translated Facebook post from the company. The animals hit the rudder for 45 minutes, causing damage to the boat that filled it with water.
In response, the captain, crew members, search and rescue personnel, port tugboats and the Moroccan Navy worked together to try to bring the damaged yacht safely into port at Tanger-Med. But despite their efforts, the ship sank near the port’s entrance. Fortunately, the crew is “safe, unharmed and sound,” per the Facebook post.
The Grazie Mamma’s demise is just one of several recent, headline-grabbing incidents involving orcas in the Strait of Gibraltar, a narrow waterway that connects the Mediterranean Sea and the Atlantic Ocean. The strait is flanked by Spain to the north and Morocco to the south.
Researchers and sailors alike are baffled by the disruptive behavior of the orcas that inhabit the strait, which are categorized as a distinct—and critically endangered—subpopulation. For the last three years, several members of this group have been colliding with vessels and, in some instances, causing so much damage the boats sink.
Since 2020, scientists have recorded more than 500 interactions between orcas and ships off the Iberian peninsula, Live Science’s Sascha Pare reported in May. That represents a small fraction of the total vessels that pass through the strait, but the unusual incidents have garnered worldwide attention nonetheless. The so-called killer whales have become social media stars, with memes and even merchandise suggesting they’re coordinating an “orca uprising.”
Scientists don’t know for sure why the orcas are targeting vessels, but they have urged onlookers to avoid assigning human attributes to the creatures, and especially to refrain from framing their actions as retaliation, reports the Washington Post’s Dino Grandoni.
“We believe this narrative inappropriately projects human motivations onto these whales, and we are concerned that perpetuating it will lead to punitive responses by mariners or managers,” a group of 35 scientists wrote in an open letter this August.
Orcas are highly social animals, and in the past, they have periodically adopted short-lived fads, such as wearing dead salmon on their heads like hats. While the vessel strikes are persisting longer than a typical fad, they might disappear just as quickly as they began, the scientists wrote. But overall, it appears unlikely the creatures are behaving maliciously or seeking revenge on humans.
“I just don’t really see it as an agonistic activity,” said Deborah Giles, a marine biologist at the University of Washington and director of the conservation research organization Wild Orca, to the Los Angeles Times’ Susanne Rust earlier this year.
So far, the behavior has mostly been isolated to the group inhabiting the waters off the Iberian peninsula—though, this summer, one incident did occur more than 2,000 miles away near Scotland.
One theory scientists have for the behavior is that orcas are simply having fun—they see boat rudders, then use their noses to push them until they snap.
“They’re pushing, pushing, pushing—boom! It’s a game,” Renaud de Stephanis, a scientist who leads the marine research group Conservation, Information and Research on Cetaceans (CIRCE), told BBC Future’s Sophie Hardach in June. “Imagine a kid of 6, 7 years, with a weight of three tonnes. That’s it, nothing less, nothing more. If they wanted to wreck the boat, they would break it in ten minutes’ time.”
Another theory is that a female orca within the group named White Gladis may be acting out because of a past traumatic run-in with a vessel. Perhaps, then, the behavior is catching on among juveniles, because they “look up to these very important females in the pod,” in orcas’ matriarchal society, as Alfredo López Fernandez, a biologist at the University of Aveiro in Portugal and a member of the Atlantic Orca Working Group, said to CNN’s Jacopo Prisco in June.
Still, some scientists point out that we, as humans, cannot presume to know the orcas’ motivation. And any attempts to guess are just that: guesswork.
“Nobody knows why this is happening,” Andrew W. Trites, director of marine mammal research at the University of British Columbia in Canada, told CBS News earlier this year. “My idea, or what anyone would give you, is informed speculation. It is a total mystery, unprecedented.”