California

Panda Bai Yun is not pregnant, San Diego Zoo officials say

Bai Yun

Bai Yun, a giant panda at the San Diego Zoo, is the mother of six cubs, five of which have been sent to China.

(San Diego Zoo)

Sad news from the San Diego Zoo: Bai Yun, the giant panda, is not pregnant, officials announced Monday, ending the civic suspense of is-she-or-isn’t-she?

As the public awaited an announcement, zookeepers have been testing Bai Yun’s urine and feces for weeks, along with using ultrasound and thermal imaging.

On Monday, the conclusion was inescapable: Bai Yun’s hormone level has receded back to a level showing that she is no longer capable of conception.

At 24, Bai Yun has had six cubs. Under the loan agreement with China, cubs born in San Diego are sent to China at age 3 or older.

Only one of Bai Yun’s cubs, Xiao Liwu, a male, remains in San Diego, along with Bai Yun and the mature male Gao Gao. The zoo celebrated Xiao Liwu’s third birthday this weekend -- meaning he could be soon be on his way to China.

With Bai Yun near the end of her reproductive years, zoo officials did not want to miss the last opportunity for the panda to achieve maternity. Whether she will have another estrus cycle is unclear, officials said.

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Gao Gao, the sire of five of her cubs, was not able to complete the necessary coupling this spring when the two were put together.

So in March, the 240-pound Bai Yun was artificially inseminated with sperm from Shi Shi, her first intended mate who had proved uninterested in physical contact when the two first arrived from China.

Shi Shi was sent back to China, but his sperm is on file at the Frozen Zoo at the zoo’s Institute for Conservation Research.

Part of Bai Yun’s fame is that she is the mother of Hua Mei, born in 1999, the first panda cub born in the United States to survive to adulthood. Shi Shi’s sperm was used through artificial insemination. Hua Mei is now in China.

Zoo officials may ask the Chinese government to allow Bai Yun and Gao Gao to retire at the San Diego Zoo in emeritus, nonreproductive status. The zoo would like the Chinese to send two younger pandas to continue the breeding program.

For San Diego area news, follow @LATsandiego on Twitter.

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