There are few things more enjoyable on a freezing day than a vigorous game of tag followed by a hearty meal.
Unless you're supposed to be the main course, that is.
These pictures show how close one man came to being a polar bear's dinner.
The target, a surveyor, was returning to his car in the remote town of Barrow, Alaska, when he saw the great white beast.
With no time to unlock the door of his vehicle and climb inside, he tried to duck out of sight.
But the hungry bear was not giving up, and a terrifying chase began.
First, the beast stood up on its furry haunches and eyed its prey. Then it loped around the car, and even climbed over the bonnet to try to reach him.
After a few laps of the car the bear almost caught up, managing to land a few heavy swipes on his prey.
The man eventually managed to take refuge in a neighbouring truck which was unlocked.
His back and head were covered in more than 100 deep scratches where the massive claws had managed to rip through his thick winter clothes and padded coat.
Barrow is the northernmost town of the United States, 340 miles north of the Arctic Circle.
Polar bears are frequently spotted around the area.
They are the world's largest land predator, and are the only animals that actively hunt humans.
Adult bears grow up to 10ft tall and can weigh 95 stone.
They are predominantly carnivores, eating seals, fish, reindeer, seabirds and even whales and baby walruses.
Environmentalists have warned that there could be as few as 22,000 left in the wild, and that they face extinction because the ice they live on is melting.
The wildlife group Polar Bears International says only one person has been killed by a polar bear in the U.S. in the past 30 years.
In Canada eight have been killed and in Russia, 19.
A spokesman said: 'In all instances in which a human was killed by a polar bear, the animal in question was undernourished or had been provoked.'
Wildlife groups have warned that increasing numbers of the giant bears have been spotted near towns and villages because they are trying to scavenge food.