5:12 PM EDT, April 1, 2011
BERLIN (KTLA) -- Famous polar bear Knut, who died suddenly at the Berlin Zoo two weeks ago, drowned after swelling of his brain caused him to collapse and fall into his enclosure's pool, experts said Friday.
It was determined that the bear suffered from encephalitis, which causes swelling in the brain and is usually brought on by an infection.
It is unclear as to what infection may have brought on the disease in Knut.
An animal autopsy showed very specific brain changes that may have been the cause of death..
The bear, who rose to fame shortly after his mother rejected him at birth in 2007, was alone in his pen Saturday, when he jumped into the water and was suddenly unresponsive, keeper Heiner Kloes told the Associated Press.
Knut was the first polar bear to be born at the zoo in 30 years.
According to reports, a crowd of about 700 people were at his compound when the 4-year-old died.
"We all held him so dearly," Berlin Mayor Klaus Wowereit told the German daily newspaper B.Z. "He was the star" of the zoo.
Officials say that since his birth, attendance at the zoo doubled and Knut-related merchandise has brought in hundreds of thousands of euros and raised awareness for the plight of polar bears.
Polar bears typically live 15 to 20 years in the wild, and can live even longer in captivity.