Dr. Kathryn Ayres has watched orcas hunt sunfish before. She was not prepared for what she saw off San José del Cabo, in Mexico's Gulf of California, in July 2024: one orca gripping a dead sharptail sunfish by its tail fin, holding it steady, while a second orca accelerated and slammed into it at full speed. "I didn't know sunfish could come apart like that," Ayres, a research scientist at the ocean-conservation nonprofit Beneath The Waves, told ABC News. "I'd seen orcas hunt sunfish before, but I'd never witnessed one using such an incredibly forceful ramming technique that the tissue fragmented throughout the water column. It was like an explosion."
A technique with a name, now: "hold-to-ram"
Ayres and her co-authors describe the newly documented behavior in a paper published this week in the journal Frontiers in Ethology. The mechanics are precise: one orca — in the observed cases, a female — grips the sunfish by its large, stubby tail fin, known as the clavus, providing a secure anchor point. A second orca, typically a male, builds up speed and rams the carcass. Just before impact, the female releases her hold, and the collision shatters the sunfish's tissue into what researchers describe as thousands of fragments that drift through the water column. Sharptail sunfish are enormous — they can grow more than three meters long and weigh up to 2,000 kilograms — making the force required to fragment one that thoroughly considerable.
Why researchers aren't sure if it's about food or fun
What complicates a simple "feeding strategy" explanation is that the sunfish were already dead in both documented cases, and their internal organs had already been removed by the orcas before the ramming took place. After the impact, a juvenile orca present in the group was seen eating the smaller fragmented pieces, while the adults fed on the larger remaining chunk that hadn't broken apart — suggesting the ramming may function partly as a way to portion food into pieces small enough for young orcas to manage. But the researchers are careful not to rule out the simpler explanation: orcas are documented to play with prey for no nutritional reason, and the sheer force involved in the ramming goes well beyond what would be needed just to break the carcass apart.
Part of a broader pattern in this specific orca population
The Gulf of California pods studied here aren't first-time record-setters. The same broader population has separately been documented flipping juvenile great white sharks to induce tonic immobility before eating their livers, and coordinating multi-orca attacks on whale sharks — the largest fish in the ocean — by targeting the pelvic area to make them bleed out. Taken together, researchers say the pattern suggests this may be a specialized pod that has developed an unusually broad and technical repertoire of large-prey hunting techniques, passed down and refined over time rather than instinctive across all orca populations.
What happens next
The research team, which includes collaborators from the University of British Columbia, Dalhousie University, the Hakai Institute, and the Leibniz Institute for Zoo and Wildlife Research, says more observations are needed to determine how often this "hold-to-ram" behavior actually occurs and what ecological role it plays. The two documented events happened slightly more than a year apart, both in the same general area — not enough, on its own, to say how common the behavior is beyond this specific group of orcas.