June 26, 2025 | The Juice Editorial Team |

The list of species that use tools is an exclusive one. Humans do it, of course. So do chimpanzees and other primates. Crows and otters use rocks to bash open snails and clams. Elephants use branches to swat flies. 

It’s time to welcome orcas to the list.

Publishing their research Monday in the journal Current Biology, biologists at Washington state’s Center for Whale Research filmed 30 examples of an orca, or killer whale, pod in the Salish Sea engaging in a behavior they dubbed “allokelping.”

“We observed whales fashioning short lengths of bull kelp stipe from complete stalks, positioning the stipe between themselves and a partner, and then rolling the kelp along their bodies,” the researchers wrote in the study.

The team hypothesizes that the orcas are using the masses of springy seaweed to groom each other. Orca skin is sensitive and prone to scaly buildups. But a good kelp rub may help remove some of that scale, and biologists noted that older whales with scalier skin were more likely to allokelp. 

Orcas are incredibly social animals. So they may also be using the tools to build bonds.   

“The main function of grooming is to help build and maintain social relationships,” study co-author Michael Weiss told Scientific American. “Sometimes, that can be more important than any kind of hygienic benefit.”

Among the pod of cetaceans, allokelping was often observed between related orcas. Grandmothers shared kelp with their grandsons, and Tsuchi, a 29-year-old orca, repeatedly kelp-groomed Tofino, her 5-year-old daughter. The behavior suggests that orcas might have even more tool tricks up their figurative sleeves.

“It tells me there’s a lot more stuff like this out there to be found — in killer whales and in other cetaceans,” Weiss says.