Dr Ben Burville, a researcher at Newcastle University, UK, has been trying for 17 years to film a seal producing the gunshot-like ‘Crack!’ sound which they make underwater during the breeding season.

Used by bull seals as a sign of strength to ward off competitors and attract potential mates, the loud high-frequency noise cuts through background noise, sending out a clear signal to any other seals in the area.

Previously believed to be a vocal sound – like the calls and whistles produced by many marine mammals – this new underwater footage clearly shows a male grey seal repeatedly clapping its flippers to produce the loud noise.

17 years to capture on camera

Published today in the journal Marine Mammal Science, the video is part of an international study led by Monash University, Australia.

Newcastle University’s Dr Burville – who tweets as the ‘Seal Diver’ – explains:

“I was diving off the Farne Islands when I first saw a large male clap underwater. The effect of the clap was instant and the rival males rapidly dispersed.

“The clap was incredibly loud and at first I found it hard to believe what I had seen. How could a seal make such a loud clap underwater with no air to compress between its flippers?

“I’ve heard the distinctive shotgun-like cracks! many times over the years and I felt sure this clapping behaviour was the source, but filming the seals in action has eluded me for 17 years.

“Then one day I had heard a couple of claps in the distance, I just hit the record button and eureka! I got it!

“Diving with seals is my passion and I have spent more time underwater with grey seals than anyone in the world.

“And yet they still amaze me every time and capturing this previously unseen behaviour just makes me realise how much there still is to learn about these incredible creatures.”

Important social behaviour

Lead author Dr David Hocking, from Monash University, said:

“The discovery of ‘clapping seals’ might not seem that surprising, after all, they’re famous for clapping in zoos and aquaria.

“But where zoo animals are often trained to clap for our entertainment – these grey seals are doing it in the wild of their own accord.

“Clapping appears to be an important social behaviour for grey seals, so anything that disturbed it could impact breeding success and survival for this species. 

“Human noise pollution is known to interfere with other forms of marine mammal communication, including whale song.

“But if we do not know a behaviour exists, we cannot easily act to protect it.”

Reference:

Percussive underwater signaling in wild grey seals.

David Hocking, Ben Burville, William Parker, Alistair Evans, Travis Park, Felix Max.

Marine Mammal Science

DOI: 10.1111/mms.12666