Mystery on the High Seas as Iberian Orcas Bump Into Boats
Researchers studying the killer whales have varying theories on why some persist in making contact with vessels
Iberian orcas that interfere with boats off the coast of Spain might just be having a whale of a good time.
Researchers trying to understand why a group of orcas around the Strait of Gibraltar have developed a taste for bumping, pushing and redirecting vessels—sometimes tearing the rudders—suspect it could be a new fad among young whales. It could also be a sign of stress from prior contact with boats, according to scientists.
“Orcas are incredibly curious animals and highly intelligent and tactile,” said Deborah Giles, science and research director for the nonprofit Wild Orca. “They like to interact with things in their environment.”
“They pick up fads, or a behavior that passes through the population, and then they move on,” she said. “We’re waiting for that part to come now when the whales lose interest.”
Two sailboats competing in a long-haul sailing competition ran into a trio of frisky orcas Thursday in the Atlantic Ocean west of Gibraltar. The black and white whales pushed at the boats and nudged the rudders underneath. One rammed a boat, but caused no damage, the crew said.
The skipper of one sailboat said the orcas came straight at the vessel and aimed for its rudders. Video of the interaction shows three killer whales in the water.
“It’s very impressive to see those wonderful animals appear all of a sudden and be so close to them,” the skipper told Ocean Race organizers after the encounter. “At the same time, it’s also somewhat frightening.”
The crew stopped the boat—inconvenient for a racing competition—and waited for the orcas to become bored, the skipper said.
Researchers have noted a surge in contact between Iberian orcas and boats off the coasts of Spain and Portugal in the past three years, sometimes resulting in damaged vessels and sunken sailboats. The Iberian killer whales, which can reach up to 20 feet as adults, can also suffer lacerations and other injuries.
Since July 2020, Portuguese and Spanish researchers with the Atlantic Orca Working Group, or GTOA, have counted roughly 536 Iberian killer whale interactions with boats around the Strait of Gibraltar. In some cases, the orcas approached the vessels but didn’t touch them. Approximately 20% of the interactions ended with a vessel damaged to the point where it could no longer navigate, according to Alfredo López, a biologist and killer- whale specialist who is part of GTOA.
Three sailboats sank after killer whales damaged rudders and caused serious water leaks, López said.
In 2023, there have been 80 Iberian killer-whale interactions in the Strait of Gibraltar. Fourteen caused enough damage that the boats were towed to shore, said López. No one has been injured in the interactions, the scientists said. Wild killer whales aren’t known to attack humans.
There are fewer than 50 Iberian killer whales that swim in Atlantic waters around the Strait of Gibraltar, according to the most recent count by GTOA. Researchers have identified a total of 39, of which 18 are adults and the rest are juveniles.
López and other scientists with GTOA have been unable to pinpoint a definitive motive for the surge in Iberian orca interest in vessels. They do know some of the culprits, however. Roughly 15 orcas have been documented interacting with boats, “each with their own interests,” said López.
Scientists have two hypotheses on the motive. Young Iberian orcas who like the tactile sensations of rubbing and pushing against a vessel are teaching each other the new behavior.
The idea that orcas could also be amusing themselves with the boats is rooted in long-term study of the marine mammals, which have been observed playing with each other and with objects in their environment.
Orcas are cetaceans of the dolphin family, and like their smaller relatives sometimes like to cruise alongside a fast-moving boat.
Other Iberian orcas might have had prior negative experiences with boats and make contact to stop the vessels and avoid the repeat of an unhappy event, said López. That theory is aligned more closely with adult behavior.
The negative experiences might be related to environmental pressures such as prey depletion, related in part to longline fisheries in the Strait of Gibraltar, the scientists said. The orcas scour the waters for fishing boats that have hooked bluefin tuna, the whales’ primary food source, and try to eat them before crews reel in the lines.
Iberian orcas in the past have suffered injuries from fishing gear and lines and a fishing boat hooked one of them a few years ago, according to López.
“All of this had to make us reflect on the fact that human activities, even in an indirect way, are at the origin of this behavior,” he said.
The interactions with boats off Iberian peninsula have been limited to the Iberian killer whale population, a small subspecies, or ecotype, within the approximately 50,000 known killer whales that inhabit the world’s oceans.
Within the killer whale species, ecotypes exist as distinct cultures and groupings, even when they inhabit the same territories as other killer whale subspecies. Each distinct culture speaks its own language and often pursues distinct food types. The groups don’t interact, and they don’t mate with each other.