Killer whales found 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 grabbing kelp fibers from the seafloor and rubbing them together for up to 15 minutes.

The behavior has been dubbed "allokelping," and it is the first time that cetaceans have been documented using external objects for skin care and to strengthen social bonds.

According to Weiss, this action may serve two main purposes: to aid in skin hygiene, removing dead skin cells or treating skin wounds; and to enhance social relationships 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 rub kelp 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-oriented, 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 say that this discovery opens up new doors to understanding the intelligence and culture of marine mammals. Drone technology is an important key to helping humans see the behavior that takes place underwater, something that was previously almost inaccessible.

Notably, the southern killer whale 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 impacts. 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 the purpose is to clean the body 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