The news of polar bear Knut's unexpected death in a Berlin zoo on Saturday has shocked and saddened people around the world, although other voices are criticizing the way he was raised.

• Polar bear star Knut dies -Society (19 Mar 11)

Early Sunday morning, people were already gathering at Berlin'sZoologischer Garten to say good-bye to Knut, the world-famous polar bear who shot to global fame in 2007 and even made the cover of Vanity Fair.

They left flowers and placed lit candles outside the zoo's gates, accompanied by messages such as: "We loved you soooooo much!" and "Bye-bye Knut!"

"I am deeply shocked," said Gabriele Thöne, the zoo's business director. "It's like a friend has left us."

Knut, pulled dead from a pool in the enclosure he shared with three females on Saturday afternoon, was just four years and three months old, well below the average life expectancy for polar bears of around 35.

The cause of his untimely death was not immediately known, said Heiner Klös, in charge of bears at the zoo. Veterinarians were due to conduct an autopsy on Monday.

TheBZdaily quoted zoo visitors as saying that Knut was sitting on rocks in his enclosure when his left leg began to shake. He then started walking around in circles before falling into the water.

Zoo workers then erected a screen around the enclosure while Knut was fished out.

The shock could be seen on visitors' faces yesterday, with many in tears. Parents found themselves having to improvise explanations for questioning children, with variations ranging from "Knut's gone on vacation" to "Knut is sleeping and doesn't want to be bothered" to "Knut's gone to polar bear heaven."

Click here for a Knut photo gallery.
"I am so sad," said Sabine, a frequent guest at the zoo who couldn't hold the tears back.

Soon afterwards the zoo was closed for the day.

Thousands of people around the globe expressed their sadness on Twitter and Facebook about the bear's passing.

But animal-rights group PETA has responded to Knut's death angrily, leveled fierce criticism against zoo director Bernhard Blaszkiewitz and bear keeper Klös.

PETA said putting Knut in an enclosure with three older female polar bears was stressful for him. The fact that he was raised by hand, by a human keeper, and developed a general orientation toward people, rather than his fellow bears, was unnatural and lead to behavioral problems, the organization said.

"Nature has now taken its revenge and spared Knut from the significant torments of captivity," said animal-rights activist Frank Albrecht, who has criticized Knut's upbringing in the past.

Wolfgang Apel, head of the German animal protection association, said the death should be a lesson.

"Knut's short and distressful life shows us again that polar bears do not belong in zoos, even if they are called Knut," he said.

DPA/DAPD/AFP/kdj

Latest news from The Local in Sweden

Noticeboard

Toytown Germany

Germany's English-speaking crowd

Toytown Germany

Rental apartments in Berlin
For home-from-home holiday accommodation, search for aBerlin apartment to rent.