Researchers document orcas smashing sunfish apart in rare behaviour

Islamabad: Researchers have recorded an unusual behaviour by killer whales off the Gulf of California, where a group of orcas was seen breaking a sunfish into pieces underwater, offering fresh insight into how the marine predators behave.

The research, released on Thursday and published in the peer-reviewed journal Frontiers in Ethology, documented the behaviour on two occasions in 2024 and 2025. Video released by the US-based NGO Beneath The Waves showed one orca gripping the tail of a dead sunfish while another rushed at the fish with force, causing it to burst apart.

Researcher Kathryn Ayres said the sunfish had already died and that the incident was not a hunting display. She said the whales may have been trying to break the fish into smaller, more manageable pieces to eat. Ayres also said play could have been a factor, noting that orcas are known to toy with their food and to tear prey apart before sharing it with others in the group, including calves and younger whales.

Ayres said, "Or it could also just be for fun. Orcas are known for playing with their food."

Scientists and conservation experts said the observations fit into a broader pattern of complex orca behaviour. Mark Peter Simmonds, science director at OceanCare, compared the scene to a social meal among humans, where interaction can matter alongside feeding. He told AFP, "Perhaps it is similar to the time when the lead human at a formal meal would carve up the roast."

Complex hunting and social behaviour

Killer whales are regarded as highly intelligent apex predators and have previously been observed using coordinated and sophisticated techniques while handling prey. They have been seen carrying out wave washing, a tactic in which they work together to create rough water that knocks seals from ice floes, making them easier to catch and eat.

Orcas have also been documented displaying other puzzling or advanced behaviour. They have been seen wearing dead salmon on their heads for reasons that remain unclear. Research published last year also found that a critically endangered population in the Salish Sea used seaweed as a tool, breaking pieces off to rub and groom one another.

Rebecca Wellard, a scientist at Curtin University in Western Australia who was not involved in the study, said the findings underscored the species’ intelligence and could encourage greater respect for them as predators in their environment.

Speaking to AFP, Wellard said, "It just really shows us how intelligent orca are."

The sunfish involved in the observations was a mola, a species known for its rounded, flattened body and fins. Sunfish can weigh as much as 2,000 kilogrammes. Wellard added that such fish do not normally explode, saying their heavy, bony build suggested the whales must have struck them with considerable force.