Orcas in the Gulf of California have been spotted ramming into one of the world’s heaviest fish and watching them explode, seemingly just for their entertainment.
Researchers captured footage of sunfish carcasses being blown to bits by orcas slamming into them in two separate events.
In one of the events, scientists spotted one orca holding a sunfish carcass by the fin, while another torpedoed toward it, blowing it into smithereens.
While the behaviour could be a way to portion off pieces of food for orca calves, researchers suspect it could also be for an entirely different reason – fun.
“Orcas often tear apart prey and share it with other members of the group, including calves and juveniles,” explained Kathryn Ayres, an author of a new study documenting these observations, published in the journal Frontiers in Ethology.
“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,” Dr Ayres said.
But the ramming method may also serve social purposes, simply as a game for the killer whales, scientists say.
Orcas, or killer whales, are known to be smart, ruthless hunters, and have been observed hunting prey larger than them – including whales – using special strategies.
But the latest strategy targeting sunfish in the Gulf of California hasn’t been described before, scientists say.
Sunfish can grow over three meters long and weigh up to two metric tons.
They swim at different depths and come to the surface to rest, when they are also the most vulnerable.
In one such vulnerable encounter recorded in 2024, researchers spotted a group of orcas interacting with a sunfish they had just killed.
A female orca held the sunfish by its tail fin, while a male accelerated and swam towards both.
The female killer whale released the sunfish just before the male rammed into it, causing the sunfish’s tissue to fragment and float in the water.
A juvenile orca then began consuming smaller bits of sunfish.
The adults were spotted feeding on remaining portions of the sunfish body, but didn’t consume the smaller fragments.
A similar event was documented in 2025, which included the same hold-to-ram and feeding behaviour.
These observations are the first times orcas have been spotted using ramming as a predation strategy, shedding more light on their tendency to coordinate and cooperate with each other.
Ramming seems to be a food processing technique rather than a means to deliver a killing blow.
Scientists hope to observe more such events involving sunfish to determine the exact significance of the behaviour in orca populations.
“Collecting good identification photographs whenever possible is key: we are still seeing new techniques of how orcas hunt and process their prey,” Dr Ayres said.
“They’re one of the most iconic marine predators in the world, yet they continue to surprise us,” she said.