Misha, a 360-kilogram Russian brown bear, killed the five-kilogram male cub, known as “Baby Bear 3”, at the Dählhölzli zoo in the Swiss capital on Wednesday, the zoo announced.
The death came after Misha put the cub in its mouth, swung it around in the air repeatedly and batted it about with its paws, a pattern of behaviour that began earlier in the week, according to media reports.
The zoo has faced criticism both for not separating Misha from the mother, Masha, and the two cubs, and for continuing to allow the other cub, “Baby Bear 4”, to remain in the presence of the father.
But zoo management issued a statement on Thursday defending its policy, saying that it wanted to give its animals the most “natural environment” possible.
“The discharge and rearing of young animals is an essential component in the life cycle of each animal,” the statement said.
The two cubs were born on January 15th and the parents were kept together because trying to separate them “would have resulted in two massive behavioural disorders”, the zoo said.
What happened is sad but “I stand by the decision”, zoo director Bernd Schildger is quoted as saying by the Berner Zeitung newspaper.
It was not clear why the male adult killed the cub, although it could have been for a number of factors, Dählhölzli biologist Cornelia Mainini said.
“It could have been a clumsy game but also the elimination of a young animal judged to be too weak,” Mainini told the 20 MInutes newspaper.
The zoo maintains that the other cub, a larger male, is in good health although it acknowledges the risks it faces.
Misha and Masha were donated to the zoo in 2009 by then Russian president Dmitry Medvedev and his wife as a gift to the city of Bern.
The bears originally came from Eastern Russia, where they were orphaned and raised by gamekeepers.
NOTE: The headline and text in this article originally stated that Misha "ate" one of the two cubs.
Although the parent put the bear in its mouth, it is not clear whether the cub was actually eaten.