PASSAU, Germany, March 26, 2008 -- Celebrity polar bear Knut is making headlines again, this time not for being cute and cuddly but rather for an apparent human fixation.

"Knut needs to leave Berlin Zoo, the sooner the better. He's had so much contact with humans in his young life that he doesn't realize he's a polar bear, he needs to get used to a life without the people who brought him up," one of his keepers, Markus Roebke, told German tabloid Bild Zeitung.

According Roebke, who helped hand-rear Knut in the Berlin Zoo, Knut is a "publicity-addicted psycho" who needs the show, the human adulation.

"He actually cries out or whimpers if he sees that there is no audience outside his compound ready to 'ooh' and 'aah' at him," Roebke said in the Tuesday edition of Bild Zeitung. "When the zoo had to shut because of black ice everywhere he howled with rage until staff members stood before him and calmed him down."

But the veterinarian charge with the polar bear's upkeep contradicts Roebke's dire appraisal.

"Not so," Andre Schuele, the zoo's vet in charge of Knut, told ABC News in a telephone interview about Roebke's comments. "I can't confirm that at all. Knut is making very good progress, he's growing up just fine, he's a very healthy animal, and everything is really normal."

Knut, now 15 months old, was rejected by his mother after he was born in December 2006, prompting some animal activists to say it was better for him to die than to be hand reared.

Zoo officials decided instead to bring him up, and the cuddly cub has become the darling of the Berliners and a major attraction, pulling in some $10 million in revenue so far.

Lonely Without Keepers

His keepers began the difficult task of weaning him a few months ago, when he became simply too big and too dangerous to have contact with them. The human keepers were forbidden to play with him for their own safety, and the celebrity bear has been finding it extremely hard to cope ever since.

According to Roebke, Knut has been howling plaintively "whenever he picks up his handler's scent. Because he's been so much in contact with his main handler, Mr. Doerflein, he will always regard him as his father"

Animal protection activists challenging Schuele's claim of Knut's "normality."

"We are observing Knut's situation with concern," said Steffen Boys, spokesman for the animal protection association Deutscher Tierschutzbund. "What's happening now was to be expected. A cuddly polar bear cub makes for a great marketing tool, which helps zoos to make a lot of money, but that has nothing to do with responsible, ethical treatment of animals. It's really sad that people don't realize that polar bears do not belong in a zoo but rather need the natural habitat to live a good life."

But Schuele insists that Knut will have a good life. "He weighs only 150 kilograms and he's simply not grown up yet," he said. "But we're talking to other zoos already preparing for his move, for when he'll be old enough and strong enough to mate with some young female polar bears at another zoo."