Knut the polar bear: Necropsy shows 'changes to the brain' likely to blame for his death

BERLIN — Brain problems apparently caused the shockingly early death of Knut, Germany's 4-year-old celebrity polar bear, the Berlin Zoo said Tuesday.

Initial findings from a necropsy performed Monday by an institute in the German capital showed "significant changes to the brain, which can be viewed as a reason for the polar bear's sudden death," the zoo said in a statement.

The zoo didn't elaborate on the changes to the animal's brain, and officials could not immediately be reached for further comment.

Pathologists found no changes to any other organs, the zoo said, adding that it will take several days to produce a final result. Further planned tests include bacteriological and histological, or tissue, examinations.

Knut died Saturday afternoon in front of visitors at the zoo, turning around several times and then falling into the water in his enclosure. Polar bears usually live 15 to 20 years in the wild and even longer in captivity.

Knut, who was born in December 2006 at the Berlin zoo, rose to celebrity status as an irresistibly cute, fluffy cub.

R.I.P. Knut: Remembering the famous Berlin Zoo polar bear's life in photos

Knut, the polar bear whose famously cute visage landed him a Vanity Fair cover and earned him legions of fans back when he was a cub in 2006 and 2007, died over the weekend of unknown causes. The celebrity bear, who was 4, died in his outdoor enclosure at the Berlin Zoo.

Zoo staffers are anxious to determine the cause of Knut's early death, considered extremely unusual for a species that can live up to 20 years in the wild and even longer in captivity. Knut had not appeared sick before his death and he was visible to 600 or 700 people gathered around the zoo's polar bear enclosure at the time of his death on Saturday.

Although it's hard to believe this beloved bear -- frozen in so many fans' memories as an energetic, full-of-life cub -- is gone, we had to smile when looking back over some of his earliest photos. Beginning in early 2007, not long after his birth, they showcase his first months in the spotlight and the special relationship he shared with his late keeper, Thomas Doerflein, who died in 2008.

We've assembled some of our favorite photos of Knut, ranging from his first year all the way to his fourth birthday last December, concluding with images of the makeshift memorial that sprang up at the Berlin Zoo over the weekend as Knut's many fans arrived to pay their respects. (For fans who live a long way from Berlin, the zoo has also set up an online memorial book for Knut.)

Above, Knut is shown at 2 months of age on Feb. 11, 2007. See more photos after the jump! (Photo credit: Peter Griesback / European Pressphoto Agency)

Necropsy performed to try to determine cause of death for Knut, Berlin Zoo's famous polar bear

BERLIN — Veterinary experts performed a necropsy Monday on Berlin zoo's celebrity polar bear Knut to try to determine why he died suddenly over the weekend.

The 4-year-old polar bear died Saturday afternoon in front of visitors, turning around several times and then dropping to the ground, and falling into the water in his enclosure.

Polar bears usually live 15 to 20 years in the wild and longer in captivity, and the zoo is hoping the investigation may help clarify what happened.

Results were expected later Monday or on Tuesday, the zoo said.

In the meantime, people continued to flock to the zoo to sign their names in a condolence book in tribute to Knut.

"Every visit to the Zoo brought happiness, because he was such a warmhearted animal and he brought us all so much fun," visitor Eveline Plat told AP Television News.

Knut, Berlin Zoo's famous polar bear, dies at age 4

Knut, the polar bear who charmed millions as an adorable cub when a Berlin zookeeper hand-raised him after he was rejected by his mother, died Saturday. He was 4 years old.

Knut was reportedly alone in an outdoor enclosure -- he shared the space with three other bears, including his mother Tosca, all of whom were inside at the time -- when he "strolled around the enclosure, went into the water, had a short spasm and died," Heiner Kloes, a bear keeper at the Berlin Zoo, told the Associated Press.

Zoogoers watched in horror until zoo staff fenced off the enclosure from view. "Everybody was asking, 'What's going on, why is Knut not moving?' " visitor Camilla Verde recalled to the AP. "All the zookeepers who put up the fences were so very sad. One of them said, 'He was our baby.' "

His exact cause of death is unknown, and a necropsy -- an animal autopsy -- is expected to be performed Monday. His death is especially troubling because of his young age. At 4, he was still essentially a teenager in human terms and hadn't even reached his adult weight or sexual maturity yet. 

For a seemingly healthy polar bear to die at age 4 is "a little bit surprising," Peter Ewins, an arctic species specialist for the World Wildlife Fund, told ABC News. "In captivity, polar bears can live longer than in the wild; to 25 or 30. Even more than 30 years old because they're not exposed to the elements and hard realities of life in the wild."

Federal judge hears arguments about Yellowstone grizzly bears' threatened status

PORTLAND, Ore. — Dueling attorneys for a conservation group and the U.S. Fish and Wildlife Service offered starkly different opinions Monday about the future of the grizzly bear population in and around Yellowstone National Park if the bear is taken off the threatened species list.

Three 9th Circuit Court of Appeals justices heard half-hour arguments and rebuttals from each side more than a year after the grizzlies were returned to the list by U.S. District Judge Donald Molloy.

The federal government is bullish on the bear's prospects, and state wildlife agencies from Montana and Wyoming have argued in briefs filed to the appellate court that officials are confident the bears won't go extinct if states are left to manage them.

Environmental groups say the bear's future is murky, and lifting protections now poses too great a risk to their survival.

Molloy's ruling, which resolved a lawsuit brought by the Montana-based Greater Yellowstone Coalition, highlighted the deaths of hundreds of thousands of whitebark pine trees over the last two decades.

Your morning adorable: Polar bear cubs explore the outdoors for the first time at Ouwehands Zoo

At the Ouwehands Zoo in the Netherlands, twin polar bear cubs born in late November ventured outside for the very first time last week.

The cubs, named Siku and Sesi (Inuit words for sea ice and snow, respectively), were born to mother Freedom and father Viktor. Their maternal grandmother, Huggies, also lives at the zoo.

If you can't get enough of Siku and Sesi, might we recommend checking out their nursery webcam on the Ouwehands Zoo's website? (As we type, the cubs are wrestling under their mother's watchful gaze, making it a little difficult to concentrate on the matter at hand.)

See more photos and video of Siku, Sesi and Freedom after the jump!

Center for Biological Diversity says it plans to sue federal government over polar bears' critical habitat

ANCHORAGE — An environmental group on Thursday gave formal notice that it intends to sue the federal government for what conservationists consider a failure to protect critical habitat for polar bears from harmful oil and gas development.

The Center for Biological Diversity sent the required notice to Interior Secretary Ken Salazar.

The Interior Department designated more than 187,000 square miles in and near the Beaufort and Chukchi seas as polar bear critical habitat, said the group's Alaska representative, attorney Rebecca Noblin.

But its agencies also have reaffirmed a Bush-era plan that authorized oil leasing in the newly designated polar bear critical habitat in the Chukchi Sea and are considering a proposal to allow Shell Oil to drill next summer in polar bear critical habitat in the Beaufort Sea.

"Unfortunately, Interior seems profoundly confused about whether to actually protect polar bear critical habitat or sacrifice it to oil companies," Noblin said.

Edinburgh Zoo to receive two giant pandas through loan program with China

LONDON — Call it panda politics.

China is sending a pair of giant pandas to the Edinburgh Zoo in Scotland as the Asian nation's deputy leader visits the U.K. to boost relations.

Vice Premier Li Keqiang, in London for trade talks with senior British officials, led the signing of the agreement Monday to send the animals to Edinburgh.

A zoo spokeswoman says the male and female pandas are about 7 years old. They will be on a 10-year loan to the zoo and are expected to arrive in the next year from China's Wolong Panda Research Institute.

Li, who is widely expected to succeed Wen Jiabao as China's next premier, is on a four-day visit to Britain to cement trade deals after trips to Spain and Germany.

RELATED PANDA NEWS:

• National Zoo's giant pandas Mei Xiang and Tian Tian to have an extended stay in U.S.

• Researchers dressed as giant pandas prepare panda cub for the wild in Chinese reserve

-- Associated Press

Photo: Yangguang, a giant panda at the Wolong Panda Research Institute in China's Sichuan province in an undated photo. Credit: Edinburgh Zoo / Associated Press

Colorado looks poised to ban hunting bears in dens

DENVER — Hibernating bears would be off-limits to Colorado hunters under a new rule that state wildlife officials are considering after a debate over whether a 703-pound black bear was sleeping when it was killed in a cave late last year.

The enormous black bear shot in northwestern Colorado set what may be a state record. But it sparked public outrage after the hunter told a newspaper that he tracked the male bear to a cave and shot it after five hours waiting for the animal to emerge.

Though the hunter said the bear was awake and snarled at him, a flurry of angry e-mails and calls to state wildlife authorities resulted.

On Wednesday, the state Wildlife Commission decided unanimously to draft a rule banning the hunting of bears in dens.

Commissioners said they've never heard of anyone "den hunting" in Colorado because it's considered unsportsmanlike. But commissioner Dorothea Farris argued that if Colorado doesn't follow other states and specifically ban den hunting, the public could sour on bear hunting altogether.

Grizzly bear deaths in Yellowstone National Park area increased in 2010

BILLINGS, Mont. — Grizzly bear deaths neared record levels for the region around Yellowstone National Park in 2010, but government biologists said the population remains robust enough to withstand the heavy losses.

An estimated 75 of the protected animals were killed or removed from the wild, according to a government-sponsored grizzly study team. That equates to one grizzly gone for every eight counted this year in the sparsely populated Yellowstone region of Montana, Wyoming and Idaho.

The deaths were blamed primarily on grizzlies pushing into inhabited areas, where bears get into trouble as they search out food in farmyards and from the big-game herds also stalked by hunters. Despite those conflicts, researchers recently reported the population topped 600 animals for the first time since grizzly recovery efforts began in the 1970s.

"The population will continue to grow with the mortalities we're seeing now," Chris Servheen, grizzly bear recovery coordinator for the U.S. Fish and Wildlife Service.

Trapped and hunted to near-extermination last century, grizzly numbers have slowly rebounded since they were declared a threatened species in 1975.