Scientists have recorded orcas ramming into a sunfish with such force that the massive fish exploded into thousands of tiny pieces, a never-before-seen hunting behaviour.
The target was a sunfish, one of the largest and heaviest fish in the world, capable of growing up to three metres long and weighing up to two tons. The behaviour was first spotted in 2024 by marine biologist Dr Kathryn Ayres, a scientist at Beneath The Waves, in the Gulf of California, where sunfish come up from deep water to rest and warm up and are one of the species most frequently hunted by orcas.
Researchers are not sure exactly why orcas do this. It could be a novel strategy for feeding their young, though experts say the orcas might simply find ramming fish to pieces fun.
How the ramming attack works
Orcas live in complex social groups and use specialised strategies to hunt different types of prey. Scientists have previously observed orcas ganging up to drown juvenile blue whales and making waves to wash seals off ice floes into the jaws of waiting pod members. But researchers say they had never seen anything like this ramming behaviour before.
Dr Ayres watched as a female orca grabbed onto the tail fin of a sunfish the group had just killed. The female held the fish steady as a male lined up, accelerated, and smashed into it, releasing the tail just before impact.
Orcas have now been spotted smashing sunfish into pieces twice, once in 2024 and once in 2025, both times in the Gulf of California. In both cases the fish was already dead when the orca hit it, suggesting the behaviour is a processing technique rather than a finishing blow.
Sharing the pieces
After the fish was blown to bits, Dr Ayres observed that the juvenile orca in the group began feeding on the smaller pieces, while the adults fed on what remained of the body but ignored the floating debris.
Dr Ayres said orcas often tear apart prey and share it with other members of the group, including calves and juveniles. The researchers suggest that breaking the fish apart might also offer nutritional benefits.
Sunfish are covered in a thick, rubbery layer called a capsule that helps them float and gives their body structure, similar to a cross between a life jacket and an exoskeleton. This layer has a unique microbiome, and the researchers suggest that smashing it apart, a process they call tissue fragmentation, could disperse these microbes into the water and help orcas absorb more of the sunfish microbiome, potentially offering nutritional or immune benefits.
Orcas playing with their food
Dr Ayres said orcas are known for playing with their food, and researchers say there is a strong possibility the ramming behaviour could simply be for fun. Marine biologists have documented groups of orcas around the world developing their own unique games to play with prey.
Orcas off the coast of Victoria, British Columbia, have frequently been seen punting dead seals into the sky. In one clip recorded by whale-watching company Eagle Wing Tours, a male orca was seen knocking a seal up to 40 feet, or 12 metres, into the air. Some scientists suggest this could be a way of teaching young orcas or practising hunting techniques, while others believe the animals may simply have a morbid sense of fun and batter dead prey for entertainment.
Identifying individual orcas
Dr Ayres said she would like to get more high-quality video showing the orcas' dorsal fins and eye patches, which would allow individual animals to be identified. She said collecting good identification photographs whenever possible is key, since researchers are still discovering new techniques for how orcas hunt and process their prey, adding that orcas are one of the most iconic marine predators in the world yet continue to surprise scientists.
Type D killer whales
Type D killer whales were only identified in 1955, after a mass stranding in New Zealand, and have been spotted only a handful of times in the past 70 years. They were initially thought to be a mutated type of the worldwide orca species, but some experts believe they are so distinct they should qualify as their own species.
Compared with other orcas, Type D killer whales have more bulbous heads, sharper dorsal fins and smaller eye patches than orca types A, B and C, which are known to dwell in Antarctic waters. They have been seen eating Patagonian toothfish, though it is unknown if they eat fish exclusively. Experts believe that if Type D orcas are confirmed as a new species, they could be the largest undescribed animal left on the planet.
