Orcas, already known for their terrifying intelligence and coordinated hunting skills, have been filmed in a never-before-documented feeding behavior: smashing giant sunfish into thousands of pieces. Researchers in the Gulf of California observed the stunning display, which could be for feeding younger orcas or simply for play.
Dr. Kathryn Ayres from Beneath The Waves, lead author of the study published in Frontiers in Ethology, described the tactic: "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." This "ramming" strategy, as researchers are calling it, was observed on two separate occasions, with orcas using a dead sunfish and repeatedly colliding with it.
Sunfish, which can weigh up to 2,000 kg, are frequent targets for orcas in the Gulf of California. In the observed events, one orca held the sunfish steady while another rammed it at high speed. The impact caused the fish's tissue to fragment, with juveniles then feeding on the smaller pieces. This tactic might make it easier for younger orcas to eat, or it could be a form of play, as orcas are known to toy with their food.
Beyond making prey easier to consume, the fragmentation of the sunfish could also offer nutritional or immunological benefits. When the tissue breaks apart, the microbiomes within it spread, potentially increasing contact between the sunfish and orca microbiomes, which researchers suggest could be advantageous.
This newly documented behavior highlights how much we still have to learn about these apex predators. "They're one of the most iconic marine predators in the world, yet they continue to surprise us," Ayres added. Further observations are needed to identify the individual orcas involved and to understand if this specific sunfish species' tissue composition makes it uniquely susceptible to this forceful processing technique.
