World | Knut Brain Problems Killed Knut Berlin Zoo says he was otherwise fine By Kevin Spak Posted Mar 22, 2011 10:25 AM CDT Copied Polar bear Knut stands behind his 'birthday cake' to celebrate his 4th birthday in the Zoo of Berlin, Germany, Sunday, Dec. 5, 2010. (AP Photo/Michael Sohn) The mysterious and sudden death of polar bear sensation Knut is mysterious no longer. A necropsy performed yesterday discovered "significant changes to the brain, which can be viewed as a reason for the polar bear's sudden death," the Berlin Zoo announced today. The zoo wouldn't elaborate on what those changes were, but it did say that no changes were found in any other organ; further planned tests include bacteriological and tissue examinations. The AP notes that polar bears can live to as old as 20 in the wild, and even long in captivity; Knut turned four in December. (Click to read about the panic attacks Knut was having last year.) Read These Next North Carolina shooting suspect once walked the red carpet. The gunman who killed 4 at a Michigan church was an ex-marine. 'We heard a big bang,' says churchgoer in Michigan Multiple people have been shot at a Mormon church in Michigan. Report an error