Fans of cuddly Knut will no longer be able to see him play with his keeper twice a day because he has become too dangerous.
The bear made his first public appearance at Berlin Zoo in March as a 20lb cub.
The boisterous seven-month-old now weighs 110lbs and the zoo is concerned about the safety of his keeper.
Zoo keeper Thomas Dörflein said: "This doesn't mean that I will never play with Knut again; it just means there are no fixed times anymore... I am always there for him.
"Knut is still a child; he needs me."
If you feel like singing along, here are the words:
Knut, der ist ein Kuschelbär
Doch hat keine Mama mehr
Trotzdem ist er frech und froh
Und der Star im Zoo
Kleiner Racker ganz in weiß
Mit vier Pfoten kuschelweich
Alle hab’n den Knut so lieb
Schön, dass es dich gibt
Knut, Knut
Kleiner Eisbär aus’m Zoo
Knut, Knut
Dir geht’s richtig gut
Knut, du bist ein Kuschelbär
Du wirst immer putziger
Laufen kannst du auch schon gut
Weiter so, nur Mut
Nuckelfläschchen in den Mund
Trinke fein, das ist gesund
Danach musst du schlafen gehen
Kleiner Knut, schlaf schön
Knut, Knut
Kleiner Eisbär aus’m Zoo
Knut, Knut
Dir geht’s richtig gut
Knut, du süßer Kuschelbär
Dich zu mögen ist nicht schwer
Streichelt man dich auf dem Bauch
Dann freust du dich auch
Deine Zähnchen sind noch klein
Kräftig beißen, das muss sein
Dann wirst du bald groß und stark
Ja, das ist doch klar
Ex-circus performer Tosca the polar bear gave birth to Knut and his brother on 5 December 2006. Tosca rejected Knut and his brother. After four days, the brother died and Knut was separated from his mother by zoo workers. He was the first polar bear to have been born and survive in Berlin Zoo for over 30 years.Being the size of a guinea pig and facing an almost certain mauling by his mother, he spent the first 44 days of his life in an incubator before zoo keeper Thomas Dörflein began handraising the cub. Knut's need for around-the-clock care required that Dörflein sleep on a mattress next to Knut's sleeping enclosure as well as feed and accompany him on his shows for the public.On 23 March 2007, Knut was presented to the public for the first time. Around 400 journalists visited Berlin Zoo to report on Knut's first public appearance to a worldwide audience.
Not only the zoo has profited from the attention surrounding Knut: several companies offer Knut-related products from ringtones to cuddly toys. Candy company Haribo decided to release a raspberry-flavored Cuddly Knut sweet in April 2007 and has promised the Berlin Zoo a share of the profits. One company even made Knut themed cough-drops. Knut was also the subject of several songs. The most successful were the single "Knut is Cute" and the song by 9-year-old Kitty from Köpenick titled "Knut, der kleine Eisbär". Knut also appeared on the March 29, 2007 cover of the German Vanity Fair magazine.
On May 1, 2007 it was announced that New York-based Turtle Pond Publications and the Berlin Zoo signed a deal for the publishing rights to Knut with the hopes of raising awareness of global warming issues.
