Killer whales groom each other with kelp

World first: orcas witnessed using seaweed scrub to cleanse each other's skin

- Helen Pilcher

KILLER WHALES, OR ORCAS, have been filmed making and then using what is thought to be the cetacean equivalent of a pumice stone.

It’s the first time that a marine mammal has been seen creating a grooming-related tool and then using it with another individual.

Lots of animals, including primates, birds and elephants, are known to use tools, but examples among marine mammals are more limited. Some bottlenose dolphins wear sponges on their beaks, seemingly to help them catch fish, while humpback whales make ‘bubble nets’ to help them catch krill. In both cases, though, the behaviour is restricted to foraging contexts, and the animals don’t modify physical objects.