Killer whales, or orcas, have just added a fascinating new behavior to their lore: crafting kelp tools to groom one another in a process researchers are calling “allokelping.” Captured via drone footage in the Salish Sea region—between Washington state and British Columbia—this is the first documented case of marine mammals using tools for social grooming
Researchers from the Center for Whale Research observed a pod of 73 southern resident orcas deliberately bite off sections of bull kelp, hold them between their bodies, and roll the kelp back and forth across each other. Some interactions lasted up to 15 minutes, and the behavior was widespread—not just random occurrences. The whales use their mouths to source and position the kelp, then their bodies maintain the motion—ingenious given their lack of hands .
What’s behind this behavior? Scientists propose two main functions:
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Skin health: Orcas shed old skin in grey, flaky patches. Allokelping might help exfoliate dead skin or treat lesions.
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Social bonding: Most pairs filmed were closely related or similar in age—hinting at a role for social cohesion in this tactile bonding ritual.
This behavior stands apart from other known oiled or kelp-related curiosities—like whales draping kelp on their heads or rubbing on beaches—because it’s intentional, tool-based, and mutually performed.
Tool use in non-primates is rare, and until now, marine examples have largely been limited to foraging: sea otters cracking shells, dolphins using sponges to search the seafloor. Allokelping adds a social component, connecting orcas to great apes and humans in terms of cultural tool use.
Drone technology proved crucial—it allowed researchers to observe behaviors never captured by boats or shore-based cameras. Despite decades of study, this behavior went unnoticed until now—a testament to both the orcas’ complexity and the power of new observation tools.
However, this discovery comes with a warning. Southern resident orcas remain critically endangered—only 73 individuals in three pods—and facing declining Chinook salmon stocks, pollution, and habitat loss. Bull kelp itself falters in warming ocean waters, threatening the very “tools” these orcas have improvised.
Protecting orca culture means protecting both their food and these newfound social rituals: losing either could erase a behavior that’s taken centuries or longer to develop.
