The unexpected phenomenon of orcas making forceful contact with vessels off the Iberian Peninsula has captured global attention since it first emerged in 2020. While news reports often use the word “attack,” marine scientists prefer the more neutral term “interaction” because the exact motivation remains unknown. This highly publicized event is unprecedented in its persistence and geographic concentration, distinguishing it from historical, isolated reports of orcas interfering with vessels.
The Specifics of the Interactions
The disruptive behavior is concentrated along the Iberian coast, primarily spanning the Strait of Gibraltar up to Galicia in northwestern Spain. These interactions are attributed to a small, distinct group of critically endangered Iberian orcas, sometimes informally referred to as the “Gladis” subpopulation, which consists of less than 50 individuals. The orcas typically target slow-moving, medium-sized sailboats, often less than 12 meters in length.
A typical interaction begins with the orcas approaching the vessel from the stern, often stealthily beneath the surface. Their focus is almost exclusively on the rudder, which they push, nudge, and ram, sometimes causing the boat to spin almost 360 degrees. This deliberate targeting often results in the rudder being bent, broken, or completely severed, rendering the vessel unsteerable. These encounters have resulted in severe damage in about 20% of reported cases, including the sinking of several vessels since the behavior began.
Leading Theories for the Behavior
Understanding the origin of this behavior requires examining several hypotheses put forward by marine biologists, as the precise motivation is not yet confirmed.
Trauma and Defense
One prominent theory suggests the behavior originated from a traumatic event experienced by an adult female, potentially the orca known as White Gladis. Researchers propose that a collision with a boat or entanglement in fishing gear led her to adopt a defensive behavior toward vessels. This initial defensive response could then have been imitated by others in the pod, even if the later participants do not share the original traumatic motivation.
Social Fad or Play
Another hypothesis views the phenomenon as a temporary “social fad” or form of play, particularly among juvenile and adolescent orcas. These younger orcas may have adopted the behavior out of exploratory interest, treating the boat’s rudder as a large, manipulable object for a social game. This theory is supported by observations that the behavior is often non-aggressive and that the core group of interacting orcas consists primarily of juveniles.
Environmental Stress
A third perspective highlights the stress and environmental pressures the Iberian orcas face, suggesting the interactions are a reaction to increased human activity in their habitat. The Strait of Gibraltar is a heavily trafficked shipping lane, and the orcas’ primary food source, the Atlantic bluefin tuna, has been under significant fishing pressure. Constant noise, vessel traffic, and resource competition may have created a baseline stress level that predisposed the animals to react forcefully to the presence of boats.
How the Behavior Spreads
The rapid adoption of this boat interaction behavior within the Iberian subpopulation is a clear example of social learning and “orca culture.” Orcas are highly social animals that transmit learned behaviors across generations and between individuals in a pod. This cultural transmission allows behaviors, such as specialized hunting techniques or transient fads, to spread quickly through imitation, even if the behavior offers no immediate survival advantage. The behavior likely started with one or a few individuals, but it has since been observed in at least 15 different orcas, including both adults and calves. This vertical transmission from adults to young, and horizontal transmission among peers, has turned an individual’s initial action into a collective, learned tradition for the subpopulation.
Measures for Sailor Safety
Maritime authorities in Spain and Portugal have issued specific guidelines for sailors to mitigate the risk of these interactions and ensure safety.
Prevention
The primary recommendation involves avoiding known orca hotspots, which are often published via “traffic light maps” and real-time alert apps by working groups like the Atlantic Orca Working Group (GTOA). Sailors are also advised to transit near the coast in shallower waters, as interactions are rare in depths less than 20 meters.
During an Interaction
If an interaction begins, the recommended protocol is to stop the engine, turn off the autopilot, and let the wheel or tiller run free. This action removes the resistance the orcas may be pushing against and can cause them to lose interest more quickly. Crew members should stay away from the steering wheel to prevent injury from sudden, sharp movements and maintain a low profile on deck. Authorities must be contacted immediately on VHF Channel 16 or an emergency number. Since the Iberian orcas are critically endangered and legally protected, sailors are prohibited from intervening or attempting to harm the animals.