A new hunting behaviour

For the first time, scientists have documented orcas using high-speed collisions to shatter the carcasses of sharptail sunfish into thousands of fragments. The behaviour was observed twice in the Gulf of California, once in July 2024 and again in September 2025, and published on Thursday in the journal Frontiers in Ethology. Underwater footage shows a coordinated sequence: one orca grips the dead fish by its tail fin while a second accelerates and rams it with full force. The impact causes the sunfish to disintegrate, scattering pieces through the water.

How the orcas do it

In both recorded episodes, a female orca held the sunfish steady, then released it an instant before a large male struck.

“We observed an orca holding the sunfish and releasing it just before another hit it at high speed, causing its tissues to fragment into thousands of pieces.”

The sunfish, already dead, offered no resistance. The sharptail sunfish (Masturus lanceolatus) is one of the world's heaviest bony fish, capable of exceeding 1,800 kilograms and three metres in length. Its laterally flattened body may make it especially prone to tearing apart under such force, Ayres told CNN, though she stressed this remains a hypothesis.

Feeding the young or just for fun?

The researchers propose two main explanations. Breaking the carcass into bite-sized pieces could allow orca calves to feed more easily. During the first observation, a juvenile was seen consuming the floating fragments while adults took larger portions.

“We think this may help the young feed more easily, or it could simply be play. Orcas are known to play with their food.”

The play hypothesis is supported by other known behaviours: orcas in Puget Sound have been observed carrying dead salmon on their heads like hats. The study notes that the ramming does not kill the prey, as the fish were already dead, suggesting the behaviour is about processing rather than hunting.

Expert reactions

Mark Peter Simmonds, scientific director of OceanCare, drew a comparison to human dining.

“It might be comparable to when people carve the roast at dinner.”

The study's authors, from Beneath The Waves and King Abdullah University of Science and Technology, say the behaviour adds to the growing catalogue of orca ingenuity. The second observation, filmed by Héctor Franz in September 2025, confirmed the pattern was not a one-off.

What the study means

The findings expand understanding of orca social learning and cooperative feeding. While the exact motivation remains unclear, the consistency across two separate events suggests a deliberate tactic. The researchers plan to continue monitoring the Gulf of California population for further instances. The study appears in Frontiers in Ethology, a journal dedicated to animal behaviour.