The world has been captivated by a bizarre and troubling phenomenon off the Iberian Peninsula: a subpopulation of orca whales (killer whales) has developed a highly unusual behavior of ramming and disabling boats, with several vessels being sunk since the behavior was first reported in 2020. This unique action, primarily targeting the rudders of slow-moving sailboats in the waters off Spain, Portugal, and Morocco, has sparked a massive effort by marine biologists and authorities to understand the cause. While some have sensationalized the events as “revenge” or an “uprising,” scientists believe the behavior is a learned cultural fad, possibly a form of play or social training by juvenile orcas that has spread through the highly intelligent marine mammals’ pod.
A Novel and Destructive Cultural Fad
The unprecedented behavior of orcas targeting boats is concentrated in the Iberian subpopulation, a small and critically endangered group. Since 2020, there have been hundreds of reported “interactions” where the orcas approach, ram, nudge, and bite at a vessel. The clear object of their desire is the rudder, which, once broken, leaves the boat disabled and can, in some cases, cause significant enough damage for the vessel to take on water and sink.
The consensus among marine biologists is that this is a learned, social behavior—a cultural “fad” similar to other transient, unusual behaviors seen in orca pods, such as temporarily wearing dead salmon on their heads. The behavior is thought to have originated with a single female, nicknamed White Gladis, and then spread among the pod, particularly among juvenile individuals who may be engaging in a form of play or social bonding around this “new toy.”
The Anatomy of a Boat Interaction
The orcas typically target monohulled sailing vessels that are approximately 12 to 15 meters long and traveling at speeds around 6 to 9 knots (11-17 km/h). The interaction is often initiated stealthily, with the pod approaching from the stern and immediately focusing on the rudder. Observers have reported seeing the whales use their heads to push the rudder or their bodies to make lever movements, sometimes pivoting the boat almost 360 degrees.
The attacks, which can last for several minutes or up to an hour, are highly coordinated. Young orcas have been observed mimicking the behavior of older individuals, suggesting a process of teaching and learning within the pod. Despite the significant damage and sinking of a handful of vessels, there has been no reported harm to humans during any of these encounters, which leads scientists to discount theories of deliberate aggression or revenge.
Searching for the Cause: Play or Trauma?
The exact catalyst for the fad remains a puzzle, though several leading hypotheses exist. One theory suggests the behavior stems from a traumatic event experienced by the originator, White Gladis, such as a painful collision with a boat or entanglement in a fishing net, which then led her to lash out at similar vessels.
However, a more recent and favored explanation is that the attacks are a form of “play behavior” that got out of hand. With the recovery of their primary food source, the Atlantic bluefin tuna, the orcas may have more leisure time, leading them to experiment with the boat rudders as an exciting, new form of stimulation. Some researchers even propose it may be a method for training young orcas, with the rudder acting as a “practice toy” for developing hunting or cooperative skills.
Navigating the Crisis and Mitigating Risk
The spike in incidents has led to new safety guidelines and research efforts by maritime authorities in Spain and Portugal. Sailors are advised to stay close to shore in shallow waters (less than 20 meters deep) or avoid the known orca hotspots entirely during peak season (typically May to August). In the event of an encounter, advice often includes stopping the engine, lowering the sails, and remaining calm to make the boat less interesting as an object of play.
Scientists are also exploring technological solutions, such as acoustic deterrents, to try and dissuade the orcas without harming them, as the Iberian orca subpopulation is critically endangered. The ongoing study of the orcas’ behavior, including the underwater “dialects” they use, aims to determine if the sounds made during boat interactions are consistent with hunting or playful calls, providing a clearer answer to this unique mystery of the sea.
