2011 Pregnancy Watch
Zoo staff confirmed late yesterday that Mei Xiang is not pregnant but was experiencing a pseudo, or false, pregnancy during the past several months. On April 20, her 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 those of a true pregnancy, making it very difficult to determine if a giant panda is actually pregnant or not. This is the fifth time Mei Xiang has had a pseudopregnancy. Giant pandas ovulate once a year—Zoo scientists will determine whether Mei Xiang should be considered for breeding again in 2010.
Staff expect Mei Xiang to return to normal, hormonally and behaviorally (including an increase in appetite and activity level), in the coming days.