Nov. 8, 2005 — Berlin this Saturday celebrated the 25th anniversary of the arrival from China of Bao Bao, the world's oldest captive panda, but with fading hopes that the bear will ever produce offspring.

"Bao Bao is a star in Berlin. The newspapers here write between 100 and 150 articles about him each year," Heiner Kloes, a biologist at the city's Zoological Garden, told AFP proudly.

"I receive emails from foreign visitors who ask me how he is and whether he is still with us in Berlin."

Lying on his back munching bamboo shoots flown in from France, the 115-kilogram (253-pound) black and white bear looks quite oblivious to the fuss.

Berliners may be particularly fond of their zoo — Kloes says there are people who visit every day and know the animals better than he does — but it is Bao Bao and his disappointing love life that grips their imagination more than any other denizen.

He arrived from China when he was two years old, not long after Beijing first began handing out the cuddly looking bears in a bid to improve foreign relations.

London, Moscow, Vienna, Washington, Madrid and Paris have all benefited.

In 1980, it was Berlin's turn and Bao Bao arrived with his first companion, Tjen Tjen.

The pair was accompanied by former Chinese prime minister Hua Guofeng, who personally presented them to the German chancellor at the time, Helmut Schmidt.

The press and the public could not get enough of the bears when they first settled in at the Zoological Garden, which lies in the west of what was then still a divided city.

Tragedy struck not long afterwards when Tjen Tjen died of a virus just as she reached the age where she could have cubs.

Since then, the zoo has repeatedly tried and failed to find a mate that could give Bao Bao offspring and help save the endangered species, which turns sex shy in captivity.

"We have contacted the Chinese authorities with a view to hiring a female panda, but without success," Kloes says.

Bao Bao was then flown to London's zoo to meet a panda called Ming Ming.

But it all went wrong when the play fight, which normally precedes the mating process with pandas, turned nasty. Ming Ming was badly injured and Bao Bao returned to Berlin.

After 10 years of negotiations between Beijing and Berlin, it was finally agreed in 1995 that the Zoological Garden could loan a female at a cost of $60,000 (50,000 euros) a year.

Berliners pinned their hopes on Yan Yan to produce a little panda.

But after numerous attempts at artificial insemination and a visit by Chinese zoologists, it emerged that Yan Yan was rendered infertile by a hormonal disorder.

China does not sell pandas, but offered to rent Germany another female, this time for the exorbitant price of $1 million a year.

The Berlin zoo blanched at the cost and refused.

"Pandas are a particularly valuable species, threatened with extinction, and it is true that the going price for renting one is always on the increase, but no zoo in Europe could afford to pay that amount of money," Kloes said.

At the moment Bao Bao and Yan Yan are living in separate enclosures and talks with China are ongoing to find another female for a lower sum.