Orcas have been observed ramming into giant fish so hard that the prey explode, possibly as a form of gory entertainment.

On several occasions, orcas were observed to hold sunfish in their jaws while a second whale smashed into the target at high speed, causing it to break into thousands of pieces. Since the fish had already been killed, scientists suggested the behaviour may represent a form of play.

Dr Kathryn Ayres, a scientist at non-profit organisation Beneath The Waves, said: “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.”

Ayres captured the first fish-ramming event on a GoPro camera in July 2024 and can be heard shrieking in shock on the audio.

“When you see a multi-ton apex predator charge a massive fish at that speed right next to your boat, the sheer acoustic thud and the resulting explosion of tissue are overwhelming,” said Erick Higuera, a marine biologist and wildlife cinematographer at Mexican non-profit Conexiones Terramar and co-author of the research.

Sunfish are among the world’s largest fish, growing to more than three metres long and weighing up to 2,000kg. They are commonly hunted and eaten by orcas.

In Ayres’ footage, a female orca is seen gripping the tail of a sunfish carcass while an adult male accelerates towards it. Just before impact, the female releases the dead fish and there is an audible crunch as the male strikes the target, leaving behind a plume of white fragments. A juvenile whale is subsequently seen eating the small pieces of flesh, while the adult orcas feed on the remains of the main carcass.

In a second instance, captured by a tourism operator in September 2025, an adult female orca was spotted holding out a dead sunfish, while a second orca executed a high-speed ramming manoeuvre, breaking it into thousands of pieces. The events were recorded in the Gulf of California, off the coast of Mexico, but it is unclear whether the same orcas were involved.

One hypothesis is that ramming is used to break the tough, rubbery sunfish into bite-size pieces for juveniles, whose jaws are smaller. But orcas are also known for social fads and boisterous games that do not have an obvious practical purpose. In the 1980s, a pod of orcas started carrying dead salmon on their head like hats, a trend that was recently revived. A subpopulation off the coast of Spain and Portugal has attracted attention for unusual interactions with boats.

“They throw kelp at each other, surf in boat wakes and engage in intricate tactical games,” said Higuera. “Play is a core pillar of orca society.”

Whatever the purpose of the behaviour, it demonstrates an impressive level of cognitive sophistication, requiring the planning and coordination of several steps, according to the findings reported in the journal Frontiers in Ethology.

Eco-tour operators increasingly use underwater drones and cameras, which are capturing new behaviours that are of interest to scientists. But there are also concerns about the disruptive impact of wildlife tourism, with Mexico issuing new regulations on swimming with orcas last year.

“If we can maintain a respectful distance and protect these animals, continuing this collaboration with tour operators will allow us to safely document mysteries of ocean life that would otherwise remain completely hidden from science,” said Higuera.