A Risso’s dolphin has shocked wildlife experts after it was filmed performing an unusual underwater ‘headstand’ - just for fun.

Drone footage captured the dolphin suspended vertically with its nose down, fully underwater and rotating slowly off the Isle of Lewis, Western Isles.

Conservationists say there have been sightings of the species ‘headstanding’ in other parts of the world they have never seen a fully submerged headstand before.

Experts from the Whale and Dolphin Conservation (WDC) said the animal could have been listening for the calls of other creatures in the water.

WDC have been researching the dolphins since 2010 and aims to gather more information about species – which get whiter with age as a result of scars caused by other Risso’s.

The area off Lewis is visited by large numbers of mothers and calves as it has a good supply of both squid and octopus which they feed on.

A spokesman for WDC said: “Researchers from WDC carrying out field work in Scotland have been left puzzled by the sight of a Risso’s dolphin performing underwater 'headstands' - something they have never seen before in the UK.

“The dolphin was spotted off the Isle of Lewis repeatedly suspended vertically underwater with his or her nose down.

“There have been reports of other species of dolphin in other parts of the world pointing nose down in the water with their tails not submerged, but the drone footage captured by the research team in Scotland is thought to be the first of a fully submerged headstand - and it is baffling the experts!

“It is not clear why the Risso's dolphin would do this but the WDC team think he or she may be listening out for the calls from other dolphins nearby, maybe having a rest, or may just be doing this in the same way we humans might - because it is fun.”