Orcas are highly intelligent creatures capable of mastering new—and often complex—behaviors, such as generating waves to toss seals off floating pieces of ice and coordinating attacks to take down blue whales, the largest animals on the planet.
Now, at least a handful of the black-and-white marine mammals living in the waters off the coasts of Spain and Portugal are seriously damaging ships. And scientists say the animals appear to be learning the behavior from each other.
On May 4, three orcas rammed into a Swiss yacht called Champagne sailing in the Strait of Gibraltar, reports Yacht magazine. After the first bump, crew members thought the vessel had collided with something, but they quickly realized orcas were pummeling the yacht. The situation eventually became so dire the ship’s crew had to call the coast guard, which sent rescuers. As they towed the boat toward a nearby port, it sank from the damage it had sustained.
Werner Schaufelberger, the vessel’s 72-year-old skipper, tells Yacht magazine that the two smaller orcas shook the rudder while the bigger one rammed the ship from the side. After that, the littler mammals mimicked the ramming action, building up speed before hitting the boat. They mainly impacted the rudder, but also hit the keel.
This is not the first time orcas have intentionally collided with ships off the Iberian coast. Since 2020, the sleek animals have sunk at least three vessels in this area, as Sascha Pare reports for Live Science. The sinkings accompany more than 500 other orca-boat interactions that scientists have documented over the last three years.
Still, these incidents account for only a small fraction of boats on the water. Alfredo López Fernandez, a biologist at the University of Aveiro and a member of the Atlantic Orca Working Group, estimates orcas touch just one percent of ships sailing in a given location, per Live Science. López Fernandez also co-wrote a June 2022 paper on orcas interacting with vessels in the Strait of Gibraltar, which he and other marine biologists described as a disruptive and novel behavior.
Scientists are mostly stumped as to why orcas in this region are suddenly attacking ships, but they have a working theory: A female orca nicknamed “White Gladis,” the individual that started this behavior, may have accidentally collided with a boat, become trapped in illegal fishing gear or experienced some other traumatic incident involving a ship. López Fernandez described this possible past event as a “critical moment of agony” that triggered this new, seemingly aggressive activity.
White Gladis is probably not teaching young orcas to attack ships. However, it’s possible they’re picking up on the behavior by simply watching her, López Fernandez tells Live Science. From there, the action has spread, because young orcas consider it “something important in their lives,” he tells the publication.
It’s also possible that ramming into boats is simply a short-lived fad that orcas will eventually move on from. Orcas have adopted other trends in the past, such as swimming around with dead fish on their heads, as NPR’s Scott Neuman reported in August. Alternatively, scientists theorized last summer that the animals might just be intrigued by moving parts on a ship—or maybe they enjoy the pressure created by a boat propeller and choose to ram into the rudder when the propeller is shut off.
No matter what the orcas’ motivations are, López Fernandez has urged onlookers to avoid applying human characteristics or emotions to the wild animals. Orcas are not maliciously attacking vessels, but rather, they’re simply responding to the presence of a foreign object in their paths. And “not in an aggressive way,” either, he told Newsweek’s Robyn White last year.
Despite their “killer whale” nickname, orcas are dolphins. Males can weigh up to 11 tons and exceed 32 feet in length. But despite their large size, orcas are extremely skilled swimmers and can attain speeds of more than 30 miles per hour.
Scientists consider the orcas living near the Iberian Peninsula to be a distinct subpopulation. Since 2011, the Spanish environment ministry has listed this group as “vulnerable,” and since 2019, the International Union for Conservation of Nature (IUCN) has listed them as “critically endangered.” In 2011, the subgroup had just 39 members.
The orcas living in the Strait of Gibraltar are no strangers to boats. Since 1999, the orcas have been observed lurking around fishing vessels to capture endangered Atlantic bluefin tuna, their main prey. The animals “find a tuna hooked, and then remove the fish before the fishermen can bring it to the surface,” per the IUCN. (Their other primary hunting tactic involves chasing tuna for up to 30 minutes until the fish are so exhausted they basically give up.)
Perhaps unsurprisingly, the strait’s fishermen “hate the killer whales,” as Jörn Selling, a marine biologist with the Foundation for Information and Research on Marine Mammals, told the Guardian’s Susan Smillie in 2020. And though the creatures are protected, rumors circulate of fishermen intentionally injuring them, such as by cutting off their fins or poking them with electric prods. Within that context, López Fernandez’s suggestion about a “critical moment of agony” prompting White Gladis to start ramming into ships seems even more plausible, though the theory remains unproven.