In an intriguing discovery, behavioural ecologist Michael Weiss observed southern resident orcas in the Salish Sea engaging in an unusual behaviour termed “allokelping.” This phenomenon arose when Weiss was reviewing drone footage and noticed an orca carrying kelp, along with the whales rolling against one another for prolonged periods. Initially dismissing it as typical whale behaviour, further footage confirmed the orcas were using strands of bull kelp for mutual rubbing.
Over two weeks in early 2024, Weiss and his team documented 30 instances of this alien interaction. Allokelping may serve dual purposes: skin hygiene through the removal of dead skin, or as a social bonding mechanism among pod members. This behaviour represents a rare instance of cetaceans utilising objects for grooming, comparable to tool use predominantly seen in primates and certain terrestrial species.
The hypothesis indicates that allokelping may address skin health issues, particularly as skin lesions have been reported more frequently among these orcas. Alternatively, it might foster social relations, since the pairs typically observed engaging in this behaviour were close relatives or peers.
Experts highlight that orcas are intelligent and socially complex animals, with large brains relative to their body size. Their sociability and curiosity, combined with advanced communication methods, contribute to the emergence of such unique behaviours. The introduction of drone technology has allowed researchers an unprecedented vantage point, revealing behaviours previously hidden from traditional observation methods.
Comparatively, while some dolphin species are known for specific tool use, the allokelping behaviour of the orcas stands out due to its potential cultural implications, focused on grooming rather than foraging. The uniqueness of this practice suggests a complex social structure, similar to customs observed in primates.
With the southern resident orca population critically endangered, the degradation of kelp forests due to human activity and climate change poses further risks. The interactions observed might provide insights into the orcas’ sporadic return to the Salish Sea, potentially looking for both nourishment and social activities.
This study opens avenues for future research on cetacean behaviours and highlights the importance of cultural practices among orcas. It underscores the urgency of habitat protection, not just for the survival of these whales but to facilitate social and cultural behaviours that may be crucial for their adaptation in a rapidly changing environment.