Berlin rallies behind baby bear Berlin Zoo has vowed it will not kill a baby polar bear amid a heated row over whether it is right to hand-rear the cub, who was rejected by his mother. Knut has been nurtured by a keeper who has slept by his side, bottle-fed him, and strummed him Elvis Presley songs. But suggestions the three-month-old should have been put down to stop him becoming emotionally and physically reliant on a human have caused outrage. "We are keeping Knut," Berlin zoo's vet told the BBC. "He's staying alive." The zoo says Knut should be strong enough to make his first public appearance at the end of this week, having amassed an army of fans who have followed his development - from walking to weaning - in the city's newspapers. He has already posed for the world-renowned photographer Annie Leibovitz as part of an environmental campaign, and next week is to be the subject of a documentary series by German broadcaster ARD. Letting Knut go But ahead of his debut, several voices have questioned the decision to keep him alive after he was rejected by his mother, a 20-year-old former performing bear from East Germany. Both Knut and his twin were left exposed to freezing temperatures shortly after they were born in December. Knut's brother died, at which point the zoo intervened to save the surviving cub. "One should have had the courage to let the bear die then," said Wolfram Graf-Rudolf, head of the Aachen Zoo, cited by the daily Sueddeutsche Zeitung. The zookeeper, who has watched the hand-rearing of two animals, said Knut will find life intolerable once bars inevitably come between him and his carer. "Each time his keeper leaves him, and he can't follow, he will die a little." Frank Albrecht, an animal rights campaigner, had started the debate in the mass-circulation Bild newspaper by declaring the zoo was violating animal protection legislation by keeping him alive. "If truth be told, the zoo should have killed the baby bear." New home Animals similarly rejected by their mothers in captivity have in the past been killed. Last December, a baby sloth was put down at Leipzig zoo after his mother refused to care for him. But each case is individual, argues Andre Schuele, Berlin Zoo's vet, and should be decided on their own merits. "Knut was a healthy baby bear when we found him and so there was no reason for us to put him down," he said. "And there's certainly no reason to do so now." To help Knut gain independence, he was already being left on his own for a couple of hours each day, and had been weaned off the bottle. Polar bears were lonesome creatures, and so spending several years without the company of other bears would not be a problem, said Mr Schuele. The cub will however eventually be introduced to others - although not back to his own family in Berlin Zoo. "He will go to another zoo," said Mr Schuele. "Eventually, we will find him a new home."