A recent study has shed light on the puzzling behavior of orcas ramming yachts in the Iberian Peninsula. While initially suspected to be acts of revenge, accident, or even just playful fun, scientists now believe these interactions are a form of practice for hunting their primary prey: Atlantic bluefin tuna.
The study, published in the journal Ocean and Coastal Management, analyzed data collected from citizen scientists – sailors who have been keenly observing the orcas’ activities. This valuable data helped researchers map the orcas’ movements and understand their relationship with the tuna population.
The researchers discovered that the orcas and tuna share similar environmental preferences, meaning they tend to be found in the same areas. The orcas’ seasonal movements closely align with the tuna’s migration patterns, demonstrating their dependence on this valuable food source.
So, how does this relate to the yachts? The researchers believe the orcas are targeting the boats’ rudders as practice for their hunting techniques. Orcas work together to catch tuna, which are large, fast-swimming fish. To isolate a tuna from its group, the orcas use a specific tactic: they ram into the fish, repeatedly, until it’s fatigued and separated from the school. Then, they drive the weakened tuna into shallower waters, where it’s easier to catch.
The orcas’ repeated ramming of the yachts’ rudders appears to mimic this behavior, suggesting that the young orcas are practicing this vital hunting technique in a playful, albeit disruptive, way.
While the behavior is concerning for sailors, the study’s lead author, Bruno Díaz López, believes it’s a natural part of the orcas’ learning process: “To play is to learn. If you have a dog and you use a toy, the dog is learning a hunting technique.”
Erich Hoyt, a researcher at Whale and Dolphin Conservation, agrees that the interactions are likely playful, but he emphasizes that they may not be solely about refining tuna hunting skills. “I think their play is more like kids’ play, without a set goal but which, in effect, helps building cognitive and physical skills.”
To minimize further negative encounters, both researchers recommend that sailors stay informed about the orcas’ movements and maintain a safe distance. While the behavior may be a temporary phase, it’s important to respect the orcas’ natural behaviors and ensure both species remain safe.
