Rare cooperation: The marine documentation of whales that surprised even veteran researchers

A new study reveals unusual cooperative behavior off the coast of Mexico: killer whales were documented slamming their heads into the carcasses of giant sunfish to tear them into pieces for the younger members of the pod.

Killer whales in the Mexican Pacific and the Gulf of California have developed a unique cooperative feeding tactic — "ramming" dead sunfish to break them apart. This is according to a study published in the scientific journal Frontiers in Ethology.

According to the documentation obtained off the coast of Mexico and the Gulf of California, the technique is performed in cooperation: one killer whale holds the giant fish by its tail, while a second killer whale accelerates and collides forcefully with the head of the carcass. The scientists emphasize that this is food processing rather than hunting, as the fish were already dead before the ramming. The calculated maneuvers open the carcass and create a field of debris that makes it easier to consume the food.

Researchers from the marine research and conservation organization Beneath The Waves explain that the aggressive dismantling significantly reduces the physical effort required from young or sub-adult killer whales, as their jaw strength is still too low to deal with such heavy and dense prey. At the same time, the technique may also assist older killer whales whose teeth are worn down.

"I couldn't believe what I was seeing," shared Dr. Ayers, who participated in the observations of the phenomenon.

During the feeding, the adults were observed consuming large chunks, while the young were content with the small and accessible fragments. The researchers note that alongside the nutritional value, it is possible that the activity also serves as a social interaction or play within the pod, but further observations are required to determine the prevalence of the phenomenon in different populations of killer whales.