Berlin - With the eyes of the world on "Cute Knut" the polar bear cub, one of Berlin zoo's other main attractions, a 22-year-old female panda named Yan Yan, died unexpectedly on Monday, the zoo said.

With the eyes of the world on "Cute Knut" the polar bear cub, one of Berlin zoo's other main attractions, a 22-year-old female panda named Yan Yan, pictured in 2004, died unexpectedly, the zoo said. [Agencies]

Yan Yan, meaning "beautiful" in Chinese, had lived at the zoo in the German capital since 1995 and was found dead Monday despite having shown no signs of being ill. Life expectancy for pandas is normally around 34.

Yan Yan was sent to Berlin in the hope that she would produce offspring with the zoo's mascot Bao Bao, who at 26 is the world's oldest panda in captivity, but she died without bearing cubs.

Heiner Kloes, one of Yan Yan's keepers, who has had his hands full caring for Knut, was said to be devastated by the news.

Knut has become a global sensation after surviving rejection by his mother. He made his first public appearance at Berlin Zoo Friday under the gaze of the world's media.

The nine-kilogram (19-pound) bear has triggered a wave of media coverage in recent days after an animal activist said he should have been put down after he and his brother were spurned by their mother following their birth in December.