For Release: July 6, 2007
Contact:
Pamela Baker-Masson 
(202) 633-3055
Sarah Taylor (202) 633-3081
National Zoo’s Giant Panda is Not Pregnant
Staff at Smithsonian’s National Zoo confirmed today that female giant panda Mei Xiang (may-SHONG) is not pregnant but was experiencing a pseudo, or false, pregnancy during the past several months.
National Zoo scientists, veterinarians and keepers were all keeping a close eye on Mei Xiang, monitoring her hormone levels and behavior, as well as conducting weekly ultrasound exams in an attempt to determine if she was truly pregnant. On June 28, Mei Xiang’s level of urinary progesterone (a hormone associated with pregnancy) began to decline. Upon reaching normal baseline levels, this decline would end in either the birth of a cub or the end of a pseudopregnancy. Based on this information, and not having seen a fetus during the ultrasound exams, Zoo researchers have determined that Mei Xiang experienced a pseudopregnancy.
Female giant pandas almost always undergo a pseudopregnancy when they ovulate but fail to conceive. During a pseudopregnancy, hormonal changes and behaviors are identical to a true pregnancy, making it very difficult to determine if a giant panda is actually pregnant or not. This is the fourth time Mei Xiang has had a pseudopregnancy: she had three prior to having her one and only cub, Tai Shan, in 2005.
National Zoo staff expect Mei Xiang to return to “normal,” both hormonally and behaviorally, in the coming days, which includes an increase in appetite and activity level. Giant pandas ovulate once a year, so Zoo scientists will determine whether Mei Xiang should be considered for breeding in 2008.
Mei Xiang is on exhibit at the National Zoo’s Fujifilm Giant Panda Habitat, along with her cub Tai Shan and the Zoo’s adult male giant panda, Tian Tian.
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