In a First, Scientists Film Wild Grey Seals Clapping to Show Their Strength

Put your hands together: At long last, a 17-year-long research effort has produced the first-ever footage of a wild grey seal “clapping” its flippers underwater.

When trained up at zoos or aquaria, these playful pinnipeds are known for delighting audiences with their applause. But the video, published last week in the journal Marine Mammal Science, shows that wild seals will clap of their own accord—no human tutors necessary.

For the Conversation, the team behind the effort led by Monash University’s David Hocking writes that the seals’ boisterous behavior probably helps them communicate, perhaps signaling strength to competitors or attracting potential mates.

Claps can now join the already impressive suite of sounds and other signals marine mammals use to navigate their underwater world. The team writes for the Conversation that many of these cues are vocal, like the chipper whistles of dolphins or the haunting songs of humpback whales. Pinnipeds, too, will work their pipes, sending “rup” and “rupe” calls ricocheting through the water. Grey seals in particular have a vocal repertoire so expansive that they’ve even been shown to imitate the sounds of vowels and other complex building blocks of human speech.

Even without exercising their vocal cords, sea creatures can cause quite the ruckus with bodily percussion, like slapping the surface of the sea with their flippers or tails. Clapping underwater, however, requires more coordination—and perhaps a keen ear.

Seal clapping behaviour | Natural History Museum

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Study author Ben Burville, a marine biologist at Newcastle University, spent years listening to the “gunshot”-like claps before finally capturing proof. More times than not, he’d hear the loud, high-frequency sounds from afar but couldn’t document the cause up close. Other researchers had mistaken the sounds for calls, but Burville, who claims to have “spent more time underwater with grey seals” than anyone else in the world “felt sure … clapping behavior was the source,” according to a statement.

But 17 years into his search, Burville finally struck scientific gold off the coast of England’s Farne Islands, home to thousands of grey seals, during the October 2017 breeding season. As his camera panned over a group of seals, including one female, a bull seal swam in close and clapped seven times in a row. Burville describes the effect as instantaneous: The other males—presumably, the first seal’s competitors—dispersed, leaving the applauding suitor to woo his potential mate.

“At first I found it hard to believe what I had seen,” Burville says in the statement. But what he’d heard was clear: The male seal’s claps were sharp enough to cut through the noisy underwater environment, sending a strong message to those around him. The authors compare the move to a gorilla beating its chest, serving both as a warning to other males and an invitation to females.

The researchers still aren’t sure how common the behavior is among other marine mammals. But grey seals’ specific anatomy, including their shorter, paw-like flippers, may be crucial to clapping. Larger species with longer forelimbs may create too much drag underwater to produce much of a sound when they bring these appendages together, says study author Travis Park in a separate statement.

But the team leaves open the possibility that grey seals could soon have company. As they write in the Conversation, “The oceans are a noisy place … and it can be important to stand out in a crowd.”

Katherine J. Wu | | READ MORE

Katherine J. Wu is a Boston-based science journalist and Story Collider senior producer whose work has appeared in National Geographic, Undark magazine, Popular Science and more. She holds a Ph.D. in Microbiology and Immunobiology from Harvard University, and was Smithsonian magazine's 2018 AAAS Mass Media Fellow.