Scientists Say Recent Orca Interactions with European Boats Appear to Be Play, Not Predation

Spanish marine researchers say a recent spate of orca interactions with sailing vessels off the coasts of Spain and Portugal appears to be driven by play behavior rather than predation, territorial defense or targeted aggression.

Renaud de Stephanis, president of Spain’s Conservation, Information and Research on Cetaceans (CIRCE), said the animals are engaging in what looks more like a game than an attack, with individuals apparently focusing on rudders and the motion they can produce when they grip or bump a boat. The pattern of incidents has increased in frequency in the region since 2020, researchers said.

The activity has prompted several rescue operations in recent days. Portugal’s National Maritime Authority reported that a pod of orcas attacked a tourist vessel near Fonte de Telha beach and another ship in the Bay of Cascais over the weekend, and that nine people were rescued following those incidents. Separately, social media footage and local reports show orcas interacting with and, in some cases, causing damage to leisure craft near Costa da Caparica and in the Strait of Gibraltar.

Researchers monitoring the animals say the phenomenon is concentrated along the western Iberian coast and inside the western Mediterranean and involves a limited number of groups. Orca Ibérica, a research group that studies the regional whales, reported recording hundreds of interactions between orcas and sailing vessels from 2020 through 2024.

De Stephanis said the episodes do not appear to reflect a mistaken identity of the boats as prey or an attempt to defend a feeding territory. "What is happening with the Iberian orcas and boats is not an attack in the sense of aggression, predation, or territorial defense," he told reporters. "This interaction is closer to a game than to an attack. They are not mistaking the boats for prey, nor are they defending territory."

Marine mammal specialists say the animals’ intelligence and social learning could explain the spread of the behavior within a subpopulation. Dr. Clare Andvik, a marine mammal expert at the University of Oslo, said the interactions can escalate when people on board try to steer away, increasing the resistance the whales experience and making the encounter more stimulating for them.

"The experience amounts to one big game of tug-of-war for the whales," Andvik said. She cautioned that although researchers interpret the behavior as play from the orcas’ perspective, it can produce serious hazards for people and vessels. Rudders have been reported broken off completely in some incidents, which can cause a boat to take on water and, in extreme cases, sink.

Authorities and researchers said the pattern of interactions appears to be a novel behavioral development rather than an established seasonal migration or a broad ecological change. Local maritime agencies have issued advisories to sailors and recreational boaters to exercise caution in affected areas and to report encounters to monitoring groups.

Scientists continue to study which social or ecological factors prompted the behavior to emerge in this region. The prevailing assessment by researchers working along the Iberian coast is that a small group of orcas developed a play-like tactic of engaging with rudders and boats and that the behavior has propagated within that group. The animals’ intelligence and capacity for social learning make transmission of such novel behaviors possible, researchers said.

The interactions have triggered concern from maritime authorities and the public because they have damaged vessels and endangered passengers, even as scientists stress that the motivation behind the actions differs from classic predatory or defensive attacks. Ongoing monitoring and reporting efforts aim to clarify the scale of the phenomenon and to inform guidelines for vessel operators in waters where orca encounters are likely.