It was either a bizarre form of play or a way to turn a large prey fish into instant chum for convenient nibbling. One orca in the Gulf of California held a dead sharptail sunfish by the tail while another orca wound up and rammed it at high speed. The sunfish exploded into a thousand pieces from the impact. Young orcas then came and grazed on the bits of sunfish floating in the water.
Diver and marine scientist Kathryn Ayres captured the underwater footage in 2024, but her paper on the event has just appeared in the journal Frontiers in Ethology.
“The cooperative ramming behavior wasn’t entirely new to me, as I had previously observed similar coordinated ramming during a hunt involving a whale shark,” she told CNN.
The exploding sunfish, however, was new. In her paper, Ayres suggested several possible reasons for the behavior. It could just be a vigorous form of play — orcas have been known to play with their food. The cooperation between the two orcas could strengthen social bonding within the pod. Or, if they had done this before and realized the fish would explode, it might have been a convenient way of generating a cloud of sunfish morsels for the young whales to feed on.
One of the world’s largest fish, the sharptail sunfish, or mola, can grow three meters long and weigh 2,000kg. That’s a lot of potential meat, even for a killer whale. The sunfish’s flattened body is unusual in large fish and could make them more likely to fly apart after a high-speed impact, Ayres suggested.
The incident occurred off the coast of Mexico’s Baja California. The Gulf of California is also known as the Sea of Cortez and is the slender body of water between Baja and the mainland.
