Scientists solve mystery of polar bear Knut's death

Knut, the star polar bear who was hand-reared at Berlin zoo after his mother rejected him, had a type of auto-immune inflation of the brain that is found in humans, scientists said on Thursday. Knut, who was just four when he drowned at the zoo in 2011, was reared by his keeper Thomas Doerflein. Knut had an epileptic fit and drowned in a pool in his enclosure.