Mei Xiang, the zoo's female giant panda had her sixth psuedopregnancy -- a common occurrance for pandas.
Mature pandas ovulate once a year and either conceive or don't, but they still experience the same signs of pregancy: decreased appetite, excessive grooming and spending more time in the den.
Mei Xiang had also been showing signs of hormonal changes in her urine, but veterinarians had been unable to observe a fetus during ultrasound exams.
Now, after several weeks of her hormone levels declining, zoo keepers can officially declare it a psuedopregnancy.
Panda births are rare in captivity. Mei Xiang gave birth to one cub in 2005.
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