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. Fans from around the world came to watch them play together, earning the zoo millions and inspiring a dizzying range of merchandise.
Knut had an epileptic fit and drowned in a pool in his enclosure. While a postmortem revealed he had encephalitis, or swollen brain, scientists had remained puzzled by the exact cause of the illness.