Polar bear Tosca,the mother of the zoo's famous four-year-old polar bear Knut, shakes off water at Berlin Zoo in 2011.
Kay Nietfield—EPA
June 24, 2015 7:38 AM EDT

MAINZ, Germany—The mother of Germany’s star polar bear, Knut, was euthanized at the Berlin Zoo Tuesday after animal welfare experts concluded that the aging animal was suffering.

Born in Canada in 1986 and formerly held by communist East Germany’s state circus, Tosca was nearly 30 years old.

“The average polar bear age is between 25 and 30 years, she was very, very old,” zoo spokeswoman Christiane Reiss told NBC News.

“Tosca’s behavior has drastically deteriorated in recent weeks. She is blind, deaf and cannot find her food,” the zoo wrote on its Facebook page after a decision was made

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