Knut the polar bear dies at age four

Knut the polar bear, who gained international fame as debate raged over whether he should be hand-reared or euthanised, has died at age four.

Knut and an unnamed twin brother were born on December 5, 2006, at the Berlin Zoological Garden. Their mother rejected them and they were abandoned on a rock in the polar bear enclosure. The zoo-keepers rescued the pair with an extended fishing net, though Knut's brother died of an infection four days later.

Knut had to be given 24-hour care, and controversy erupted in March, 2007, when the German tabloid Bild-Zeitung quoted animal-rights activist Frank Albrecht as saying that the bear should have been killed rather than be raised by humans.

Wolfram Graf-Rudolf, the director of the Aachen Zoo (also in Germany), agreed, stating that the zoo-keepers "should have had the courage to let the bear die" after it was rejected by its mother. In response, a group of children protested at the zoo, holding up placards reading "Knut Must Live" and "We Love Knut". Others sent numerous emails and letters asking for Knut's life to be spared, and Berlin Zoo vowed not to harm him.

Knut was presented to the public on March 23, 2007. The controversy and media attention surrounding him lead to Knut being a consistently popular exhibit at the zoo, and Knut-related merchandise became a multi-million-euro industry.

On March 19, Knut collapsed and died in his enclosure in front of 600-700 visitors. They described how the bear's rear left leg began shaking before he became agitated and started convulsing. He then fell backwards into the enclosure's water pool, and drowned before he could be rescued by zoo-keepers. He was four years old. (Polar bears in captivity can live as long as 30 years.)

The cause of the convulsions is not yet known, though a necropsy has revealed evidence that Knut had a brain disease.