Anyone who's ever had a nightmare about stuffed animals coming to life can relate to what Thomas Doerflein is going through. The zookeeper who's been celebrity polar bear cub Knut 's surrogate mother since the little camera hog was an adorable ball of fluff finds himself on the business end of an uncomfortable truth: Polar bears are ferocious predators.
Nearly six months old, Knut has grown to 62 pounds on a diet of porridge, fish, meat, and cat food. He draws 5,000 daily visitors to the Berlin Zoo to watch Doerflein play with him, but his once-delightful nipping now comes with a full measure of sharp carnivore teeth. "It only hurts when he gets angry," the keeper tells Reuters. (Read more Knut stories.)