Overview

• Researchers documented southern resident killer whales in summer 2024 tearing bull kelp stalks with their teeth and rolling the pieces between bodies to remove dead skin.
• The behavior, named allokelping, may be the first recorded example of toolmaking in marine mammals that simultaneously benefits two individuals.
• Repeated observations show close relatives and similarly aged whale pairs most frequently engaging in the kelp-grooming ritual.
• Individuals exhibiting higher levels of molting skin participated more often, indicating that kelp brushes serve an exfoliation function.
• With fewer than 80 southern residents remaining, scientists emphasize the importance of protecting kelp forests and continued monitoring of this critically endangered population.