By PETER SIMPSON

Last updated at 21:42 17 October 2007

There is no mistaking the excitement on the four-year-old boy's face as he swims alongside a beluga whale many times his size.

And the whale seems to be enjoying the company, too.

The boy, named Yang Yang, will ride his playmate bareback to entertain the crowds between the sailing events at the 2008 Olympic Games in Beijing.

Yang Yang, who has been swimming since he was one, was chosen to swim with the five-year-old whale by staff at Qingdao Polar Ocean World in China's eastern Shandong Province.

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They first appeared in public together during the country's National Children's Day in the summer and proved such a success that it was decided to make them an Olympic attraction.

The boy's parents think he is one of the luckiest in China, but others might disagree, bearing in mind the country's reputation for pushing young athletes to extremes.

Yang Yang is one of about 280million children in China - representing about one-fifth of the child population of the world.

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The whale's wild peers, however, are an endangered species.

There are fewer than 80,000 beluga whales left in Arctic waters, with St Lawrence, Cook Inlet, and Alaskan belugas classified as endangered.

The recently completed Qingdao Polar Ocean World is home to more than 10,000 ornamental fish, as well as white whales and polar bears - and is one of the largest polar marine animal parks in the world.