Knut the Polar Bear Dies at Berlin Zoo of Brain Problems

Exact cause of famous 4-year-old bear's death still uncertain.

March 22, 2011, 4:17 PM

March 22, 2011 -- As with most moments in the short life of the world's most famous polar bear, Knut's final seconds were captured on camera.

In new disturbing video posted on YouTube you can hear spectators in the Berlin Zoo last weekend watch in curiosity and then horror as the young bear first starts going in circles around his own shadow, then convulses and falls to his death in a pool of water.

The Berlin Zoo says a test performed on the famous polar bear shows that "significant changes" in the animal's brain led to his death. A necropsy, according to the zoo, did not show changes in any other organs. The zoo is trying to pinpoint the exact cause of death.

Polar bears usually live at least 15 to 20 years in wild, and even longer when removed from the harsh Arctic elements. This is leaving many to question how Knut's life in captivity may have contributed to the death of the just 4-year old bear.

The German branch of PETA repeatedly raised concerns with the Berlin Zoo about Knut's captivity and fame during his short life. "We have been after this zoo ever since they made Knut a tourist attraction to his detriment," said PETA President Ingrid Newkirk. "When he was small cuddly and fuzzy he was cute and everybody loved him. But then he grew and became boring and everyone lost attention. He was not hand fed anymore or babied and loved. He was put in an enclosure about 1 millionth of the space he would be in nature."

Knut's twin brother died soon after birth. They were rejected by their mother, a former East German circus bear, immediately after they were born. Knut was raised by a zookeeper who bottle-fed him and taught him to swim. The little bear became an instant celebrity after he was introduced to the world in March 2007. But like so many of his human celebrity counterparts, he was a child star who had trouble adjusting as he grew up.

At first many questioned whether it was wise to hand-raise the animal. Knut reportedly had issues with fellow bears that he at times shared an enclosure with. Many also claimed that Knut became obsessed with applause and often grew withdrawn when people did not show their approval of his antics.

"He was growing nuttier and went from being called 'Knut the cute' to 'Knut the nut,'" said Newkirk. "He was suffering from panic attacks, and he would sway and then mimic tourist taking photos of him. Some people thought that it was cute, but this repetitive behavior was a result of mental anguish."

"Knutmania" waned some but remained strong enough to earn the Berlin Zoo millions, even as countless groups criticized the institution for forcing him to live in such a small space.

The world famous San Diego Zoo houses four adult polar bears in an environment as seemingly removed from the frozen reaches of the Arctic as you can go. A spokeswoman rejects criticism that polar bears are too big and too wild to live in small zoo enclosures.

"Our polar bears are doing well," said Christina Simmons. "There aren't release programs for polar bears in captivity, because they are large predatory mammals and they don't have enough food in many places in the wild due to climate change. They are actually becoming more of a threat to humans in the wild, so at this point it makes no sense to release them."

Scientists say climate change and the alteration of their natural habitat with the loss of sea ice in many areas are threatening polar bears around the world.

"The long term outlook for polar bears is grim," said Geoff York, head of Arctic species for the World Wildlife Federations global program. But he contends that zoos play a role in finding a solution. "We simply can't learn everything in the wild. Zoo's have a potential role to play in conservation and educating the public about polar bears, but when it comes to negatives it's all about maintaining high standards."

The San Diego Zoo re-launched its polar bear plunge exhibit last year, and says it is one of many zoos looking to expand its facilities as the threat of climate change grows on the polar habitat.

Dr. Randi Meyerson, polar bear survival plan coordinator for the Association for Zoos and Aquariums, says new polar bear exhibits are being designed to cater to the roaming nature of polar bears. "We give them environments where they can do similar activities as they do in the wild and we can keep them busy. We also don't go out and trap healthy bears, so they typically don't have to acclimate to the loss of vast living expanses."

In death, at least for now, "Knutmania" looks like it will live on. The news of his sudden death has sparked tributes across the social media world. On his Facebook fan page, many have continued to pay tribute. Fans are now attempting to collect donations to erect a memorial in his honor.

Outside the Berlin zoo, PETA has already laid its own plaque and it reads, "Not a single day in freedom, a life without dignity, forgive us Knut."

As for Knut, even in death he may be an attraction. There are reports that the animal will be stuffed and displayed at the Berlin museum.

ABC News Live

ABC News Live

24/7 coverage of breaking news and live events