A panda at the Memphis Zoo is definitely pregnant, officials there said Wednesday. Ya Ya, a giant panda, was artificially inseminated in January after she and a male companion failed at mating the old-fashioned way. Since then, the zoo has closely monitored her as the potential due date drew near for the 6-year-old panda.
"I'm excited, but I'm also cautious because we have a long way to go before the birth," said Chuck Brady, the zoo's president.
Panda pregnancies cannot be confirmed until shortly before the delivery date. Gestation lasts about 133 days, which means Ya Ya could give birth soon.
An ultrasound showed that Ya Ya's fetus recently began growing, The Commercial Appeal newspaper reported. After the insemination, she was in a period called a "diapause" in which the fertilized egg doesn't mature in the uterus.
Zoo officials have been watching Ya Ya round the clock this month for behavioral changes such as pacing, agitation and becoming more secluded.
"We've just entered into the growth phase," Brady said. "This is a critical stage, and we'll have to monitor Ya Ya carefully."
She and a male panda, 8-year-old Le Le, are on loan to the zoo from China. Ya Ya and the cub will be off exhibit for about three months, zoo officials say.
Pandas are notoriously poor breeders _ one reason their species is endangered — and females have only three days a year in which they can conceive.
Only three other U.S. zoos — those in San Diego, Washington and Atlanta — have giant pandas. The most recent panda cub born in the U.S. was Mei Lan in Atlanta last September.