Orcas Make a Dead Sunfish Explode With a Coordinated Body Slam, Possibly to Feed Juveniles or Just Have Fun

On camera, the moment looks almost cartoonish. A female orca holds a dead sunfish steady by its tail. A second orca comes in fast and rams it. The impact is so violent that the sunfish's tissue doesn't just tear; it bursts apart into thousands of drifting fragments, as a pillow struck hard enough to blow its stuffing everywhere. Off camera, the researcher filming can be heard reacting, a muffled, unmistakable sound of surprise.

Researchers had never documented orcas ramming prey this way. Once the fragments began drifting, a juvenile moved in and started eating them.

“We think this may help younger orcas feed more easily, or it could also just be for fun. Orcas are known for playing with their food,” first author Kathryn Ayres said in a press release.

Ayres and her colleagues describe the behavior in a study published in Frontiers in Ethology. Their findings draw on two encounters in the Gulf of California, one in July 2024 and another filmed by Héctor Franz in September 2025.

Orcas Ram Sunfish in the Gulf of California

Weighing as much as 4,400 pounds, a sunfish offers orcas an enormous meal. The fish travel between deep and shallow water, sometimes reaching the surface to warm themselves or seek relief from parasites. Those visits also bring them within reach of orcas, which frequently prey on sunfish in the Gulf of California.

One detail changes how researchers interpret the collisions: the sunfish had already died. The orcas were therefore breaking down their food, not trying to kill it.

During the 2024 encounter, the group included a female, a male, and a juvenile. The female used the sharp-tail sunfish’s broad tail fin as a handle while the male struck the body. Afterward, the juvenile collected loose pieces while the adults ate from the remaining carcass.

Orcas repeated the same general maneuver during the second encounter more than a year later.

Smaller Pieces for Younger Orcas

Orcas regularly tear apart prey and share it with other members of their group, including calves and juveniles. Breaking up a huge sunfish could similarly make its flesh easier for a younger animal to eat.

The behavior could therefore represent a form of parental investment. Although the researchers cannot say whether feeding the juvenile motivated the collision, the smaller fragments gave it access to pieces it could manage more easily.

The impact may also change more than the size of the meal. A jellylike coating called a capsule covers sharp-tail sunfish, and both this layer and the skin carry their own communities of microorganisms. Blasting the tissue apart mixes those microbes into the surrounding water.

Those microbes could provide extra nutrients or even influence the orcas’ immune systems. For now, though, that is only a possibility. The team did not show that microbes played any role in the behavior.

Identifying the Orcas Behind the Behavior

Both meals were sharp-tail sunfish. Researchers do not know whether other sunfish would burst apart the same way or whether something about this species makes its flesh especially easy to break up.

They also could not tell whether the same orcas appeared in both encounters. The shapes of their dorsal fins and white eye patches work almost like fingerprints, helping researchers distinguish one animal from another. Clearer footage could show whether the same group uses the technique again.

“Collecting good identification photographs whenever possible is key: we are still seeing new techniques of how orcas hunt and process their prey,” concluded Ayres in the press release. “They're one of the most iconic marine predators in the world, yet they continue to surprise us.”

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