BERLIN — Germany's celebrity polar bear Knut died from drowning after collapsing due to swelling of his brain and falling into his enclosure's pool, an expert said Friday.
Pathologist Claudia Szentiks said a necropsy of the 4-year-old bear who died suddenly two weeks ago showed he was suffering from encephalitis, an irritation and swelling of the brain that was likely brought on by an infection.
She said it was unclear specifically what caused the brain swelling, but that experts had ruled out rabies, botulism and bovine spongiform encephalopathy, also known as mad cow disease.
Szentiks also rejected allegations from animal-rights groups that he was traumatized by living in a zoo environment, saying that there were no indications of any chronic stress.
- Inside JFK's Cool Dad Moment - After John Jr.'s White House Jungle Gym Fall
- PEOPLE Exclusive: Kendra Wilkinson Reveals Why She Can't Really Have a Six-Pack Right Now
- 15 Foods You Never Thought to Grill - But Should
- Scott Disick Is Allegedly Off the Wagon: 'He Knows He's Screwing Up,' Sources Say
- Dethroned! Matt Stonie Defeats 8-Time Champ Joey Chestnut in Nathan's Annual Hot Dog-Eating Contest
She added that even if Knut had not drowned after his collapse, he would not have survived the damage from the encephalitis.
Knut died March 19 in front of visitors at Berlin 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.Story: Knut, Berlin's beloved polar bear, dies in his compound
Knut, who was born in December 2006 at the zoo, rose to celebrity status as an irresistibly cute, fluffy cub.
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.Story: Newt (the politician) mourns Knut (the polar bear)
The bear went on to appear on magazine covers, in a film and on mountains of merchandise.
Doerflein, the zookeeper who raised him, died in 2008 of a heart attack.
Copyright 2011 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.