Experts said Knut, the four-year old German polar bear (photo, from ctv.ca), drowned when he fell into a pool of water in his enclosure after collapsing because of a brain swelling on March 19.
According to first indications from post-mortem examinations at Berlin Zoo there were “significant changes to the brain” and large amounts of water were found in his lungs.
An infection probably caused these changes which led the bear’s brain to swell, senior vets said.
“We believe that this suspected infection must already have been there for a long time… at least several weeks, possibly months,” Achim Gruber, a professor of veterinary medicine at Berlin’s Free University, said.
He also said that even if Knut had not fallen into the water, it is likely that he would not have survived.
In the coming weeks, a pathology team will keep searching for the exact cause of the illness of the star polar bear.
Although polar bears can live until they are 15 or 20 years old in the wild and until they are 30 in captivity, Knut died suddenly at the age of four in front of hundreds of people.
He became world famous in December 2006 after his mother rejected him at birth, along with his twin brother who only survived a couple of days. Thomas Doerflein, Knut’s main caregiver, camped out at the zoo in order to give the cub his bottle every two hours.
After that the polar bear appeared on magazine covers, in a film and on mountains of merchandise.
Since his birth Knut has generated more than 5m euros ($7m) in extra income for the zoo of the German capital, in a craze called Knutmania.
In 2008 Mr Doerflein died of a heart attack.
Knut’s death was described as awful by Berlin Mayor Klaus Wowereit, who told BZ newspaper : “We all held him so dearly. He was the star of the Berlin zoos.”
Fans became angry when reports said that Knut may be stuffed in order to be put on display at Berlin’s Museum of Natural History, in an exhibition on climate change.
A “Stop the Stuffing of Knut” demonstration is planned in front of the zoo, according to Reuters.