Key points
- Behaviour may serve social bonding or skin health purpose
- Researchers call this unique behaviour “allokelping” in whales
- Drone footage captured 30 kelp massage events in 2024
- Discovery highlights tool use and complex whale social culture
ISLAMABAD: Researchers have observed orcas in the North Pacific engaging in a behaviour dubbed “kelp massage,” where the whales use strands of seaweed to rub one another.
Using drone footage, scientists recorded killer whales selecting, biting, and shaping tubular pieces of kelp, which they then placed on a companion’s back, appearing to use it as a massaging tool, according to the BBC.
The study, published in Current Biology, suggests this could be a form of tool use—rare in marine mammals—indicating purposeful behaviour with a specific social or health-related function.
Lead researcher Dr Michael Weiss from the Centre for Whale Research (CWR) noted that during 12 days of drone observations between April and July 2024, the team recorded 30 such interactions among the endangered Southern Resident orcas off Washington State’s coast. “When we fly the drone over these whales, we almost always see at least one pair engaged in this kelp massage,” he told the media.
Social grooming
The team coined the term “allokelping” to describe this marine version of allogrooming—a common behaviour in primates, where social grooming helps to strengthen bonds and remove parasites.
Professor Darren Croft from the University of Exeter, who co-authored the study, emphasised that physical contact plays a key role in maintaining social relationships among these highly social whales.
The drone technology, used over the past decade, has offered researchers a unique aerial view of orca behaviour beneath the water’s surface, revealing how they interact and socialise. It also allowed them to see how these large animals used relatively small pieces of kelp to make physical contact more precise.
Skin-care function
Some evidence suggests that orcas with more visibly shedding skin were more likely to engage in kelp massage, indicating a possible skin-care function—perhaps a way to “scratch an itch.”
It remains uncertain whether this behaviour is unique to the Southern Residents or more widespread among other orca populations or species. Still, the finding offers fresh insight into the complex social lives of killer whales, according to the BBC.
The Southern Resident killer whale population has been studied for over 50 years, originally to investigate threats to their survival. This long-term research has revealed the importance of social roles, including that of grandmothers, and the sacrifices made by females to support their offspring.
Dr Weiss called the discovery further evidence of the whales’ unique culture and the need to aid their recovery.
