These Killer Whales Make Tools From Kelp to Massage Each Other in a Newly Discovered Grooming Behavior
Dubbed “allokelping,” it might be a unique cultural phenomenon that’s as endangered as the orca population itself
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Killer whales, also known as orcas, are incredibly intelligent apex predators. As such, researchers have been observing the species for decades. Specifically, the Southern Resident killer whales—a population consisting of three pods in the Pacific Northwest—are some of the most studied orcas in the world. But even these well-known animals still have surprises in store.
In a first, scientists have observed Southern Resident killer whales collecting stalks of seaweed and using them to massage each other. The scientists describe the behavior in a study published last week in the journal Current Biology, saying it represents the first known instance of cetaceans making and using tools for grooming purposes.
Officially called “allokelping,” the behavior involves an orca biting off the end of a stalk of kelp and pressing it against another orca—often a close maternal relative or peer of a similar age—so that the cetaceans can rub it between them. The interactions might have to do with skin health and strengthening social bonds.
“In primates, including humans, touch moderates stress and helps to build relationships,” Darren Croft, a co-author of the study and executive director of the Center for Whale Research, says in a statement. “We know killer whales often make contact with other members of their group, touching with their bodies and fins, but using kelp like this might enhance this experience.”
As for skin health, scientists already know that whales and dolphins get rid of dead skin in several different ways, so allokelping might be another grooming solution, he adds. Some evidence suggests that whales with more dead skin engage in allokelping more frequently.
Fun facts: Strange orca behaviors
- Orcas are known to develop behavioral trends in different populations.
- These have included wearing “dead salmon hats,” ramming into boats and hunting great white sharks.
The researchers discovered allokelping last year, when they received more advanced drones than the ones they’d previously been using to observe the orcas in the Salish Sea, which sits off the northwestern corner of the United States and the southwestern corner of Canada.
“With this high-definition video, we could see this little length of what turned out to be bull kelp between them,” Michael Weiss, lead author of the study and a behavioral ecologist at the Center for Whale Research, tells Science’s Annika Inampudi. “I was like, ‘Oh, that’s an interesting single observation.’ But once we knew what to look for, we started seeing it everywhere.”
The researchers documented 30 allokelping bouts during an observation period of 12 days. The instances involved orcas of all ages and sexes, as well as from all three pods. Some cetaceans push kelp around in another behavior suspected to be a form of play or skin maintenance called “kelping”—but allokelping is different, because it involves the preparation of a tool and the engagement of two orcas.
In the study, the team writes that the new behavior could mark the first tool use in a wild animal that benefits multiple individuals at once, as well as the first tool use in a non-human creature that relies on the core of the body, not an appendage, to operate the tool. They also write that allokelping could mark the first known instance of marine mammals “manufacturing” tools—in this case, by detaching the kelp from its stalk.
Research describing tool use in animals, however, is often a subject of debate. Other scientists, for example, have reported that bottlenose dolphins make and use tools when they protect their noses with marine sponges as they hunt for fish on the ocean floor, per Science.
Either way, researchers have documented less tool use in aquatic animals than in land animals, Georgetown University behavioral ecologist Janet Mann, who studies tool use in bottlenose dolphins and didn’t participate in the new research, tells Scientific American’s Elizabeth Anne Brown. This is likely because, among other reasons, most aquatic animals don’t have appendages made for holding tools.
As such, “this kind of feels like a moment in time for cetaceans, because it does prove that you don’t necessarily need a thumb to be able to manipulate a tool,” Philippa Brakes, a behavioral ecologist from the nonprofit Whale and Dolphin Conservation who also did not participate in the study, tells CNN’s Marlowe Starling.
“In one sense, the findings are not a surprise, given the intelligence of these animals,” Vanessa Pirotta, a wildlife scientist at Macquarie University in Australia who was not involved in the study, writes in an article for the Conversation. However, “because orcas differ so much, we don’t know whether other pods have discovered or taught these behaviors.”
In other words, allokelping might be a cultural behavior unique to Southern Resident killer whales. Unfortunately, this population of orcas is critically endangered, meaning this culture might one day disappear with them.
“If we lose them, we may never see this behavior on the planet again,” Weiss tells the Guardian’s Oliver Milman. “We don’t just lose 73 whales; we lose everything they have been doing for thousands and thousands of years.”
