Braving sub-zero temperatures, she has thrown caution — and her clothes — to the wind to tame two beluga whales in a unique and controversial experiment.

Natalia Avseenko, 36, was persuaded to strip naked as marine experts believe belugas do not like to be touched by artificial materials such as diving suits.

The skilled Russian diver took the plunge as the water temperature hit minus 1.5 degrees Centigrade.

Belugas are famed for the way in which their faces are able to convey human-like expressions. Certainly Matrena and Nilma seemed to enjoy frolicking with Natalia.

The taming of the whales happened in the Murmansk Oblast region in the far north-west of Russia at the shore of the White Sea near the Arctic Circle branch of the Utrish Dophinarium.

An area of the sea is enclosed  to stop whales and dolphins getting out and instructors tame the mammals before they are transported to dolphinariums around the world — a practice many animal conservationists consider cruel.

Belugas have a small hump on their heads used for echo-location and it was thought that there would be more chance of striking up a rapport with them without clothes as a barrier.

The average human could die if left in sub-zero temperature sea water for just five minutes.

However, Natalia is a yoga expert and used meditation techniques to hold her breath and stay under water for an incredible ten minutes and 40 seconds.

There are around 100,000 belugas in the wild.  The first to be held in captivity was shown at Barnum's Museum in New York in 1861, and there are belugas in aquariums and sea life parks across Europe, North America and Asia.

Their large range of 'facial expressions' comes from them having a more flexible bone structure than other whales. Certainly these two had a big smile for the naked Natalia ;-D