BERLIN (AFP) – Berlin's superstar polar bear Knut, who died suddenly over the weekend aged just four, likely fell victim to undiagnosed brain damage, his zoo said Tuesday.
Berlin Zoo said in a statement that a preliminary necropsy conducted Monday revealed "significant changes to the brain, which could be seen as the reason for the sudden death of the polar bear".
It said no other organ damage had been identified but that the examination of the cadaver was continuing.
Knut, who was found lifeless in the pool in his enclosure on Saturday afternoon, had shot to fame as a cuddly cub after being abandoned by his mother and reared by hand.
The first public appearance of "Cute Knut" attracted 100 camera crews from around the world and the cub generated millions of euros (dollars) for Berlin Zoo in lucrative merchandising and extra entrance fees.
But once he grew into a strapping adolescent and then adult, animal welfare groups began to worry that he was displaying abnormal behaviour because of all the attention.
He would sway to and fro and even imitate people taking photos by lifting a paw to his face.
Devastated fans have been leaving flower bouquets, written tributes and photos of Knut at his former den at the zoo, while an online condolence book has drawn more than 4,000 messages.
Meanwhile, a fan organisation started collecting donations for a memorial to the bear.
"Knut will live on in the hearts of many visitors but we want to create something lasting for generations to come with this memorial so that the uniqueness of this animal personality will endure," the chairman of the Friends of the Capital Zoos, Thomas Ziolko, said.
[Image via Victor Hinterleitner for Knutisweekly.com, Creative Commons licensed]