Pandemonium over possible panda baby

Stop the presses! Alert the bloggers! The two adult giant pandas at the San Diego Zoo mated Tuesday, zoo officials announced, raising hopes of an offspring this summer.

So far, Bai Yun and Gao Gao are two for two during their stay at the zoo under a loan from the Chinese government.

The pair mated in 2003 and the male Mei Sheng was born that August. They mated again in 2005 and female Su Lin was born that August.

In San Diego, where zoo animals are celebrities, the sex life of the pandas is followed closely by media and public. Female pandas are in season only two to three days a year, and not at all during years when they have young cubs.

This year, for the first time, the public was able to watch Bai Yun and Gao Gao mating. The zoo’s panda cam on its website (www.sandiegozoo.org) trained on the two during the act.

Gao Gao is proving to be a different kind of male than his predecessor, Shi Shi, who refused to mate with Bai Yun. She even got grouchy about it one year, to no avail.

Bai Yun was impregnated through artificial insemination and gave birth to Hua Mei, a female, in 1999. Shi Shi’s failure to perform cost him his post at the zoo.

Shi Shi was returned to the Chinese in 2002 and replaced by Gao Gao. Hua Mei was also sent to China -- under the loan agreement, all offspring are property of the Chinese.

With two adults and two youngsters, the San Diego Zoo has more giant pandas than any zoo in the U.S. The only U.S. zoos to have the animals are San Diego, the National Zoo in Washington and zoos in Memphis and Atlanta; pandas are considered the most popular animals ever to be put on display in the U.S.

One reason for the panda loan is to allow scientists to work at unraveling secrets of the panda’s reproductive system.

With its habitat in China being gobbled by modernity and its reproduction cycle so tricky, the panda population in the wild has dwindled.

Although much has been learned by watching the pandas, zookeepers were caught by surprise when Bai Yun went into estrus earlier than anticipated. Still, Gao Gao was in the area and the act was consummated quickly, officials said.

Bai Yun and Gao Gao were then separated. Except when mating, male and female pandas are known to bite and scratch each other.

It will be months before zookeepers will know if conception occurred. In past pregnancies, it became apparent that Bai Yun was pregnant only a few days before she gave birth.

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tony.perry@latimes.com