BERLIN -- Hundreds of fans of Knut the polar bear flocked to his zoo enclosure Sunday to mourn the sudden death of the celebrity who burst into the limelight as a cuddly, fluffy cub hand-fed by his keeper.
The beloved four-year-old died Saturday afternoon in front of hundreds of visitors, taking keepers, animal experts and fans by surprise. The life expectancy of polar bear in the wild is between 15 and 20 years, but animals in captivity normally live even longer because they are not exposed to hunger, thirst or infections.
"I can't comprehend what happened there. He was happy before, there were no signs of anything - it's so shocking," said fan Eveline Litowski, who said she had come to the zoo to find out more about Knut's early death.
Litowski was among those who crowded around Knut's empty compound Sunday, laying down red roses and white stuffed polar bears, lighting candles or putting up pictures of Knut with personal messages for him. Many children had drawn pictures of Knut or written farewell poems for their beloved bear.
Knut was rejected by his mother at birth, along with his twin brother, who only survived a couple of days. He attracted attention when his main caregiver, Thomas Doerflein, camped out at the zoo to give the button-eyed cub his bottle every two hours, and went on to appear on magazine covers, in a film and on mountains of merchandise.
Dozens of women known as die-hard Knut fans - some of whom reportedly even tried to hide in the zoo's spacious park to spend a whole night with him - had assembled in front of the bear's empty enclosure Sunday afternoon. Many sobbed and shared their memories.
"I've been crying nonstop since I heard about his death," said Ingrid Rommel, a 65-year-old widow from Berlin, who said had been visiting Knut weekly since his birth on December 6, 2006. She credited him with helping her get over the death of her husband.
Heidemarie Vogel, a 58-year-old woman from Potsdam near Berlin, remembered that Knut had sometimes raised his paw when she called over to him.
"It was as if he was waving to me - so nice," Vogel said tearfully. "My only consolation is, that now he is finally united with his keeper in heaven."
Doerflein, the zookeeper who raised him, died in 2008 of a heart attack, earning front page headlines in a German newspaper as "Knut's daddy."
Soon after Knut and Doerflein's first public appearance in early 2007, fan clubs sprung up across the globe, including in Japan, the United States and Germany. They followed the bear's every move, including his weight battle - he had a weakness for croissants - or plans to move to a different zoo.
"Knutmania" led to a 2007 Vanity Fair cover with actor Leonardo DiCaprio shot by photographer Annie Leibovitz, a film and plush likenesses. Though the zoo has never released exact numbers, Knut merchandise including postcards, key chains, candy and stuffed Knuts have brought in hundreds of thousands of euros (dollars).
Even after packing on hundreds of pounds (kilograms) and trading in his soft fuzz for yellowish fur, fans remained loyal. News of Knut's death on Saturday afternoon around 3 p.m. spread instantly and internationally via Twitter, Facebook and text messaging.
"We received condolences from all over the world: Australia, New Zealand, Honolulu," bear keeper Heiner Kloes told German news agency DAPD.
He said Knut's body on Sunday morning was pulled out of the pool in which he died, after it had been emptied of the most of the water. Experts will conduct a post-mortem Monday to identify the cause of death.
Some fans already had their own theories. Nadine Hipauf said she worried somebody may have poisoned Knut - whether on purpose or not.
"My biggest fear is that somebody may have thrown something in for him to eat," Hipauf said.
Others claimed that Knut had died of stress, saying he was bullied by the three female bears he shared the enclosure with - Tosca, Nancy and Katjuscha.
"They should have given him a compound of his own," retiree Brigit Krause said. "The ladies were constantly harassing him."
Tomislav Skaro contributed reporting from Berlin.