A recent study published in *Current Biology* reveals that Southern Resident orcas in the Salish Sea, between British Columbia and Washington state, use tools made from kelp to groom each other. Researchers, led by Michael Weiss, observed the orcas using drones and found they not only use the tools but also manufacture them.
The orcas modify kelp stalks, pressing and rolling pieces (about 60 cm long) against each other. This behavior, called "allokelping," involves the whales adopting an "S" shape during the process. This grooming behavior has been observed across different sexes, ages, and social groups.
Orcas are more likely to groom closely related individuals. This suggests a potential hygiene function, as whales with more shedding or dead skin are more likely to be groomed. This finding highlights the intelligence and social complexity of orcas, showcasing a unique cultural practice.
While similar behaviors have been documented in other whale species, "allokelping" appears to be a unique cultural practice among these orcas. Experts note that more research is needed to confirm the extent of this behavior and to fully understand its purpose. This group of orcas is also endangered.
Factors contributing to their endangerment include habitat degradation, persistent pollutants, and a decline in prey quality, such as Chinook salmon. This study underscores the importance of continued research and protection of orcas and their environment, emphasizing the need for conservation efforts.