Five people were rescued after a pod of critically endangered Iberian orcas rammed into a sailboat several times, causing it to sink off Portugal’s Costa do Caparica, near the nation’s capital, Lisbon, on Sept. 13.
None of the people on board suffered any injuries, according to the Portuguese maritime authority. The boat, owned by yacht rental company Nautic Squad, sank bow-first but was later transported to a nearby port.
The same day in Cascais Bay, around 60 kilometers (37 miles) northeast, tourists aboard a second sailboat also reported orcas knocking against the side of their vessel. This year, more than 80 such orca interactions, most of them involving sailboats, have been reported along the coast of Spain and Portugal.
The Iberian orcas form a subpopulation of killer whales (Orcinus orca) found in the Strait of Gibraltar, numbering roughly 37 individuals. They’ve been listed as critically endangered on the IUCN Red List since 2019.
The first orca-boat interaction was reported in May 2020, and there have since been more than 750 encounters where orcas push or ram into boats. Prior to the latest incident, orcas caused at least six boats to sink. Vessels can avoid orcas by sticking close to shore near their hunting zones.
The subpopulation’s numbers plummeted after the collapse of its preferred prey, the Atlantic bluefin tuna (Thunnus thynnus), due to overfishing. Today, the tuna population has recovered, and some scientists think the abundance of food has given orcas more time to play.
Boat ramming joins a roster of other curious orca behaviors, such as wearing dead salmon on their heads like hats, and using kelp to massage each other.
Researchers say it’s likely just a handful of orcas behind most of the incidents. One, which they’ve nicknamed Gladis Blanca after the former scientific name of the species, Orcinus gladiator, is believed to have started the fad.
The International Whaling Commission (IWC) has warned against calling the behavior an attack, as the orcas are more likely engaging in some form of play.
“The behavior has more in common with fads seen elsewhere and seems associated with play or socializing, perhaps encouraged by the recent increased abundance and availability of prey,” a 2024 report on a IWC workshop stated. “The use of words such as ‘aggression’ or ‘attack’ to describe such interactions is thus inappropriate.”
Orcas may be using sailboats to train their young to hunt, one scientist, Bruno Díaz López, chief biologist at the Bottlenose Dolphin Research Institute in Spain, told The New York Times in August 2024. His research team found that boat ramming is usually done by young orcas, and has observed adults teaching the behavior to juveniles.
“This is like a training toy,” Díaz said. “It’s a shame that we humans are in the middle of this game, but they are learning,” he added.
Banner image: Iberian orcas pictured off the coast of Spain. Image courtesy of circe.info.
This story first appeared on Mongabay
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