San Diego Zoo announces giant panda Bai Yun is pregnant (and may give birth to twins)
The San Diego Zoo has announced that its 17-year-old resident female giant panda, Bai Yun, is pregnant. Bai Yun was born at China's Wolong Giant Panda Research Center and came to the San Diego Zoo in 1996 as part of a scientific exchange program. (Zoo officials and a Chinese diplomat announced late last year that the loan of Bai Yun and a male panda, Gao Gao, would be extended for an additional five years.) Since then, she's given birth to four cubs: Hua Mei, Mei Sheng, Su Lin and Zhen Zhen.
Pandas' reproductive systems are still largely a mystery to researchers, and although zoo staff knew Bai Yun had mated with Gao Gao in April, they were unable to confirm her pregnancy until a recent ultrasound, our sister blog L.A. Now reports.
The ultrasound revealed that Bai Yun is carrying not just one but two fetuses. But, senior research tecnician Suzanne Hall is quick to point out, an ultrasound conducted during one of Bai Yun's previous pregnancies also revealed two fetal cubs early on. Subsequent ultrasounds later in her pregnancy, however, showed that the second fetus had been reabsorbed, and only one cub was born. "We were left to wonder if that fetus was somehow less viable than the other and, therefore, died prematurely or if Bai Yun’s body selectively pruned her litter of two down to one," Hall wrote on the zoo's blog. (You can view a video of the ultrasound process at the San Diego Zoo's website.)
The National Zoo points out that when pandas give birth to two cubs in the wild, typically only one survives. Since Bai Yun has never carried twins to term, zoo staff doesn't know how she'll react if she gives birth to both cubs. The zoo expects her to give birth next month, according to L.A. Now, and it will definitely be interesting to see what happens. In the meantime, Bai Yun has been removed from the zoo's public observation area so she can begin her "denning" process.
Bai Yun's first cub, Hua Mei, was the first giant panda born in North America to survive to adulthood, although she was sent to live in China in 2004. She now lives at her mother's birthplace, the Wolong Giant Panda Research Center, where she's given birth to six cubs of her own -- three successive sets of twins!
-- Lindsay Barnett
Photo: Bai Yun with her then-4-month-old cub, Zhen Zhen, in December 2007. Credit: Denis Poroy / Associated Press