(CNN) Michael Weiss, a behavioral ecologist, was looking through fresh drone footage of the Salish Sea orca pods he studies when he noticed an odd behavior: Some of the orcas were rubbing against one another for as long as fifteen minutes at a time. He also noticed one of the killer whales had something green in its mouth.
Weiss claimed that whales do strange things, so at first he didn’t give it much thought. However, additional investigations showed that his drone camera captured comparable images. When I zoom closer, it’s evident that they are rubbing against one another with this piece of kelp.
Weiss and his colleagues recorded 30 instances of these odd encounters in a two-week period in 2024. The scientists discovered that the southern resident orcas, a particular kind of killer whales, were engaging in an activity they called “allokelping,” in which they were pulling strands of bull kelp from the seafloor to roll between their bodies. According to the researchers’ latest article, which was published on Monday in the journal Current Biology, allokelping may be a means for pod members to socialize with one another and practice skin hygiene.
For the first time, cetaceans—marine mammals that include whales, dolphins, and porpoises—have been seen grooming with an object.
Behavioral ecologists claim that the use of tools is uncommon in the animal kingdom. However, when it does occur, it’s usually to attract partners or obtain food. According to Weiss, the study’s lead author and research director of the Center for Whale Research in Washington state, this is a very unusual approach to use an object.
Allokelping theories
Weiss and his team speculate that the allokelping behavior may be caused by two factors.
One explanation can be hygiene, such as cleaning or eliminating dead skin. In order to maintain their smooth and aerodynamic bodies, cetaceans frequently shed dead skin. According to Weiss, allokelping may be a means of treating skin lesions, especially gray patches, which are becoming more common among southern resident orcas.
Weiss clarified that since the whale pairs observed engaging in this behavior were typically close relatives or of comparable ages, the alternative theory is that allokelping is a means of enhancing social ties.
Deborah Giles, an orca biologist at the SeaDoc Society who was not involved in the study, remarked, “These guys are really socially bonded.” She went on to say that while this behavior is intriguing, it is not totally unexpected.
Giles noted that orcas have enormous brains relative to their body size and are tactile and inquisitive. He also mentioned that certain areas of the killer whale’s brain are more developed than those found in humans. Even the dialect of each orca community is unique.
According to Janet Mann, a behavioral ecologist at Georgetown University with 37 years of experience studying marine mammals, cetaceans also have sensitive skin. Orcas have been observed rubbing against algal mats and smooth-pebble beaches in Canada. However, she said that it’s uncommon to witness two killer whales working together with a tool to exfoliate one another.
According to Mann, the study demonstrates how little we actually understand about cetacean behavior in the wild.
Without advancements in drone and camera technology, which have given scientists a whole new perspective on the complicated behaviors of cetaceans, Allokelping probably would not have been discovered, according to Mann. Whales have traditionally been viewed from boats or the shore, providing a restricted view of what is going on in the water. Drones, however, provide an aerial perspective of the activities of marine life just below the surface. This population has probably been allokelping for some time, but we are only now able to observe it, she said.
Cultural phenomenon
According to Giles, orca scientists who have access to drone footage will likely be watching for this kind of activity moving forward.
However, other cetaceans are known to use tools besides killer whales. According to Mann, who has researched the bottlenose dolphins in Australia’s Shark Bay, some of the dolphins have been seen meticulously removing and utilizing sponges to frighten up animals on the seabed. This is a sophisticated activity that only a small portion of the population displays.
Other bottlenose dolphins create mud-ring plumes that capture fish by slapping the ground in a circle with their tails. Additionally, bubble nets have long been employed by humpback whales to capture animals.
The scientific community is divided on whether these instances qualify as tool use, although they are all actions associated with food foraging. The potential advantages of allokelping for relationships and skin health make it special; in other words, it seems to be a cultural activity.
According to Philippa Brakes, a behavioral ecologist with the nonprofit Whale and Dolphin Conservation who was not involved in the study, the concept of allogrooming (with tools) is primarily unique to primates, which is what makes it remarkable. Because it demonstrates that you don’t necessarily need a thumb to operate a tool, this seems to be a moment in time for cetaceans.
“This new research tells us quite a bit about how important culture is for these species,” said Brakes, who specializes in studying social learning and culture in cetaceans. Every population—in this example, southern resident orcas—has a distinctive way of communicating, a particular way of feeding, and, more recently, a particular way of using tools.
According to Brakes, culture offers animals an amazing means of adapting to a constantly changing environment, just as it has for people.
She pointed out that it’s even more justification to make sure that we preserve both their habitat and behavior.
A completely novel find
With a population of only 74, southern resident killer whales are in fact federally protected and considered critically endangered in both the United States and Canada. Additionally, the ecosystem as a whole is deteriorating as a result of the drop in bull kelp brought on by human activities that disturb the seabed and increasingly frequent heat waves brought on by climate change.
According to Giles, kelp forests are also an essential source of nursery habitat for young chinook salmon, which form a major component of killer whales’ diet. According to Monika Wieland Shields, creator and director of the charity Orca Behavior Institute, Southerners have been spending less time in the Salish Sea over time, maybe as a result of declining prey.
This finding makes me wonder if allokelping is one of the reasons Southerners keep going to the Salish Sea on occasion, even when salmon populations are low, Shields wrote in an email to CNN.
New fields of inquiry are currently being uncovered by the research.
The fact that this cetacean data point is entirely new makes it extremely significant, according to Dora Biro, a University of Rochester animal cognition expert who was not involved in the study.
Examples of terrestrial tool usage are far more common than in aquatic settings, Biro, who has primarily researched tool use in wild chimpanzees, remarked. She is now working on a grant proposal with Weiss team to better understand the purpose of the behavior.
But for Brakes, there doesn t necessarily need to be a purpose: The objective may just be social bonding, and that would still make it a tool.
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