WATCH: Seal's Never-Before-Seen Underwater 'Gunshot' Clap Leaves Scientists Stunned

Footage from an international study led by Monash University has captured a gunshot-like sound made by grey seals clapping underwater.

Clapping seals have been seen before at "zoos and aquaria”, but they've never been captured on film clapping completely underwater, according to study lead author Dr David Hocking.

Researchers were shocked at the gunshot-like ‘crack’ sound the male grey seal produced when he clapped his paw-like flippers together.

It took naturalist and diver Dr Ben Burville 17 years to capture the loud clap on camera.

“The clap was incredibly loud and at first I found it hard to believe what I had seen,” Dr Burville said.

"How could a seal make such a loud clap under water with no air to compress between its flippers?"

The claps are said to be a part of the seals' mating behaviour -- used either to attract potential mates or to ward off potential competitors.

Burville has spent most of his life underwater with the sea creatures. He says they can be predators, known to kill porpoises -- but in his 20 years of diving with the animals he has found them to be gentle creatures.

"Seals are inquisitive, intelligent animals, genetically closer to bears than dogs”.

If the clapping behaviour is any indication, there is still a lot to learn about even well-studied animals, according to Dr Hocking. He believes better knowledge about the animals will allow for the greater protection of them.

“Human noise pollution is known to interfere with other forms of marine mammal communication... but if we do not know a behavior exists, we cannot easily act to protect it”.

Dr Ben Burville is a visiting researcher with Newcastle University, UK.