SUMMARYOrcas in the Gulf of California were filmed repeatedly ramming sunfish with enough force to break the animals into fragments. The behavior was documented in a paper in Frontiers in Ethology and may reflect cooperative hunting, social learning, or play among orcas. Researchers linked the strikes to broader patterns of coordinated hunting seen in other prey species.
Credit: Kathryn Ayres
There have been numerous accounts in recent years of orcas ramming boats—and sometimes sinking them. Scientists believe this may be a form of culturally learned behavior passed down through generations. Now we have fresh examples: orcas in the Gulf of California were filmed teaming up to ram sunfish with so much force that the carcasses exploded into small fragments. While orcas have been known to use force to remove flesh from prey, this is something different, according to a new paper published in the journal Frontiers in Ethology.
“We think this may help younger orcas feed more easily, or it could also just be for fun," said co-author Kathryn Ayres of Beneath The Waves, a nonprofit organization promoting ocean health. "Orcas are known for playing with their food.”
Orcas engage in cooperative hunting strategies that can involve striking or killing animals—sometimes eating their prey, sometimes not—so the behavior could be described as social interaction, play, or practice as a mode of social learning. Orcas have been observed ramming whale sharks as another orca held the prey steady. Other cooperative strategies include herding mobile rays, blocking an escape path while hunting white sharks, and deliberately producing waves to bump penguins off ice floes.