Orcas are known to be smart and ruthless hunters. They've been observed hunting a variety of prey, with some species, such as whales, larger than themselves. They use a wide range of strategies to hunt and kill prey, but now, in the Gulf of California, researchers have observed one that hasn't been described before.
"We document how one orca holds the sunfish and lets go just before another orca hits it at high speed, causing the tissue to break apart into thousands of pieces," said first author of the Frontiers in Ethology article, Dr. Kathryn Ayres, a scientist at Beneath The Waves, a nonprofit organization promoting ocean health. "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."
Sunfish blown to bits
Sunfish can grow more than 3 meters (10 feet) long and weigh up to 2,000 kg (4,400 pounds). They move through various depth layers but come to the surface to rest, thermoregulate or seek parasite removal. In surface waters, they are vulnerable to predation.
In the Gulf of California, they are among the species most commonly hunted and eaten by orcas. The current observations are based on two independent hunting events that occurred a little more than one year apart.
In July 2024, Ayres observed how a group of orcas, including a juvenile, interacted with a dead sharp-tail sunfish they had killed previously. A female orca held the sunfish by its large tail fin—an effective point of grip—while a male orca accelerated and swam toward both.
Shortly before impact, the female released the sunfish. The ramming caused the sunfish's tissue to fragment and float in the water. The group's juvenile then began consuming smaller bits of sunfish. The adults fed on what remained of the body but didn't consume the smaller fragments.
In September 2025, a similar event, filmed by Héctor Franz, followed the same hold-to-ram and feeding behavior.
Small bites
The high-impact ramming behavior caused substantial disintegration of prey tissue. Ramming has not previously been described as a predation strategy by orcas. Both events suggest that the orcas followed a coordinated and cooperative strategy, with one orca stabilizing the carcass so the other could hit it more precisely.
The sunfish were already dead in both events, so the ramming is thought to be a processing technique rather than a means of delivering a killing blow.
The gelatinous layer that covers sunfish, known as the capsule, and their skin host a distinct microbiome. If this tissue is shattered, the microbial taxa inhabiting it are dispersed into the water, where they alter the nutrient composition. Tissue fragmentation could therefore facilitate contact between sunfish and orca microbiomes, which could provide nutritional or other benefits, such as immune regulation.
The observed behavior could be interpreted as a form of parental investment, the researchers pointed out. Dividing the carcass into more manageable pieces for the calf aligns with previously observed behaviors.
"Orcas often tear apart prey and share it with other members of the group, including calves and juveniles," said Ayres.
'They continue to surprise us'
Yet, this doesn't rule out the possibility that the interaction also served other social purposes: It could simply have been a game for the killer whales.
For sunfish, the interaction could provide new insights into the species' characteristics. So far, tissue fragmentation has been observed only in sharp-tail sunfish. This suggests that disintegration could be a species-specific structural response of sharp-tail sunfish tissue to high-energy impacts that may not apply to other, larger sunfish species.
It's unclear whether the same orcas were involved in both events. This highlights the need for more high-quality footage—especially of orcas' dorsal fins and eye patches—to identify individuals.
"Collecting good identification photographs whenever possible is key: We are still seeing new techniques of how orcas hunt and process their prey," concluded Ayres. "They're one of the most iconic marine predators in the world, yet they continue to surprise us."
More information
Fragmentation of Sharp-Tail Sunfish (Masturus lanceolatus) Caused by High-Impact Ramming Behaviour in Orcas (Orcinus orca), Frontiers in Ethology (2026). DOI: 10.3389/fetho.2026.1835536
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Citation: Orcas filmed ramming one of the world's heaviest fish so hard it explodes, possibly for fun (2026, July 23) retrieved 23 July 2026 from https://phys.org/news/2026-07-orcas-ramming-world-heaviest-fish.html
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