Killer whales discovered using seaweed to 'massage' each other

A surprising discovery has amazed scientists: killer whales know how to use kelp as a tool to rub each other's skin.

The strange behavior of killer whales was recorded by behavioral ecologist Michael Weiss through drone videos in 2024 in the Salish Sea (USA) and was recently published.

Over two weeks, Weiss and his team recorded 30 instances of killer whales picking kelp strands from the seafloor and rubbing them together for up to 15 minutes.

The behavior, dubbed "allokelping," is the first time cetaceans have been documented using external objects for skin care and social bonding.

According to Weiss, this action may serve two main purposes: assisting in skin hygiene, removing dead skin cells or treating external wounds; and enhancing social bonds between individuals in the same group, usually individuals of the same litter or close relatives.

Scientists say this isn't too surprising, as killer whales are highly social, have developed brains, and have distinct "dialects" between populations. However, the fact that they use kelp to rub together as a form of "massage" is a behavior that has never been recorded before in the ocean.

While some dolphins have been known to use bubbles or mud to hunt, all of these are for the purpose of finding food. In contrast, allokelping is more cultural than survival, similar to the tool-based “social care” behavior of primates like monkeys and chimpanzees.

Two whales use kelp to "massage" their skin - Photo: Whale Research Center

Experts such as Janet Mann (Georgetown University) and Philippa Brakes (Whale and Dolphin Conservation) both said that this discovery opens a new door to understanding the intelligence and culture of marine mammals. Drone technology is the key to helping humans see the behavior that takes place underwater, something that was almost inaccessible before.

Notably, the Southern Orca population is now listed as critically endangered, with only about 74 individuals remaining. Meanwhile, kelp, the main tool for this behavior, is also declining due to climate change and human impact. The loss of both habitat and cultural behavior is a major concern.

Scientists are beginning to ask an interesting question: do killer whales return to the Salish Sea not only for food, but also to practice a unique cultural tradition like allokelping?

Whether it's for cleaning or simply a way to "relax" and strengthen social relationships, this behavior reveals a surprising truth: killer whales are not only apex predators in the ocean, but also creatures with rich mental lives, knowing how to use tools without needing thumbs like humans.

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MINH HAI

Source: https://tuoitre.vn/bat-ngo-phat-hien-ca-voi-sat-thu-dung-tao-bien-de-mat-xa-cho-nhau-20250624232803289.htm