Orcas scrub each other clean with bits of kelp

image via New Scientist

June 23, 2025, 4:00 PM

• •Killer whales off the coast of North America are using kelp as a tool to groom each other, a behavior observed through drone footage.
• •The orcas break off kelp stalks and rub them on each other's bodies, potentially for hygiene or social bonding.
• •Scientists are investigating if this kelp-based grooming has health benefits by examining skin bacteria.
• •This behavior, involving deliberate body movements, suggests a strong social connection within the orca population.

Drone footage has revealed a rare instance of tool use among killer whales, where they break off kelp and use it to groom each other. This behavior, observed in orcas off the coast of North America, involves the whales carefully selecting and manipulating kelp stalks. The orcas rub the kelp on each other's bodies, potentially for hygiene or to strengthen social bonds. Researchers are exploring if this kelp grooming has health benefits and is more widespread than currently known.

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