The online community was amazed when they discovered a dog abandoned in a vast snowy expanse, being safeguarded by a magnificent white bear.

This is the adorable – and extraordinary – moment a wild polar bear pets a chained-up sled dog in the Canadian wilds.

Polar bears weigh 330-990lbs and can easily kill a dog, especially one on a chain. But this footage, shot by David De Meulles of Manitoba, shows the bear gently stroking the placid animal on the head.

‘I had no idea what was going to happen, and then sure enough he started petting that dog, acted like he was a friend,’ De Meulles told CBC. I just so happened to catch a video of a lifetime.’

Unlikely pals: This polar bear was seen petting a sledding dog at a northern Canadian dog-breeding center. The hardy sled dog, which is on a chain, seems unbothered by the bear.

De Meulles was taking tourists to see polar bears when they came across the dogs, chained up on the property of local man Brian Ladoon.

Ladoon breeds the rare sled dogs, which are impervious to the cold – and clearly fearless too.

At first, the bear towers over the chained animal, which placidly lies at its feet.

But then the beast reaches out tenderly with its right paw and gently – if clumsily – brings it down over the dog’s head.

It sniffs the dog, which has barely reacted, and pets it again, more confidently this time. Then it switches to its left paw and begins rubbing the dog’s head.

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Bearing it: The dog happily lets the bear pet it with both its paws – at first gingerly, but soon with smooth, gentle motions.

At this point the pooch, apparently slightly irritated by its wild companion, stands up and begins to walk off – forcing the bear, which has the dog’s chain wrappedaound its front legs – to back off too.

‘I’ve known the bears to have somewhat friendly behaviour with the dogs, but for a bear to pet like a human would pet a dog is just mind-blowing,’ De Meulles said.

‘It was a beautiful sight to see, and I just can’t believe an animal that big would show that kind of heart towardaother animal.’

Ladoon told CBC that the dogs, which are bred for the cold, see the chilly area as a ‘paradise’ and are rarely troubled by predators, save the occasional attack by wolves.

There have been ‘scares’ with polar bears, he says, but the ‘primitive and fearless’ dogs keep the nasty bears in their place.

And, it seems, reward the nice ones with a little playtime.

Time’s up: Eventually, the dog seems to tire of the bear and gets up to wander off, forcing the bear to back up, as the chain is wrappedaound its forelegs.