They're cute, they're cuddly, but these bears are not frothy, man

Polar bears get away with a lot because they're so nicely dressed. Apparently they're every bit as grumpy as grizzlies. You wouldn't want to leave your children near them because they'd probably be eaten in seconds.

But polar bears are good in commercials, so their private life has been hushed up by the studio publicity machine. In advertising, bears are winsome and funny. In the Coca-Cola commercial – the latest in a campaign that's been running for several years now, on and off – the polar bears are great family people too. These bears – Mum, Dad and three cubs – live in a spacey blue-white right world, like the moon with added snow, round a pool with pixilated currents. The computer animation is so sophisticated that their white fur ripples and shines convincingly. You can see every hair, just as if they'd been using an expensive Victorian hair oil.

But they're clearly not aiming for realism, in a world where Coke is drunk at sub-zero. It's all pitched well below the Plimsoll line of the unconscious, with glistening fur balls mooching as amiably as Tom Hanks, and bear cubs circling the screen on floating snowy islands.

Coca-Cola makes its ursine characters grunt with pleasure – plaintive puppy grunts, not brutal bearish ones.

It's completely hypnotic; the computer animation means the bears have bulk and texture and believable body language, and the logic of dreams means they seem absolutely at home in that blue-white space. By the same token, drinking Coke in winter, outside, seems perfectly natural, something that we'd all have a little doggy grunt about. Life tastes good.

The whole thing's a semiotician's paradise, an object lesson for those Euro-intellectuals who love commercial design for its use of signs and symbols and for its appeals to the dark and deep, to the inner child. And for once they'd be right. Clearly Coke think white-on-white works, or they wouldn't bring it back, again and again.

Twenty-something years ago a cartoon bear presented a now- forgotten fizz called Cresta. This was a cool bear with shades and a catch-phrase: "It's frothy, man." He was a clever, funny British bear, but the techniques used in the Coke advertisements make him look like a million years BC.