Congratulations may be in order for Mei Xiang, the giant panda at the National Zoo in Washington D.C., but veterinarians are cautioning everyone to not get too excited since the possible pregnancy is in its early days.
"It is too early to determine if the tissue is a completely viable developing fetus as there is the potential that the fetus could be resorbed," the Smithsonian's National Zoo & Conservation Biology Institute said in a press release alongside an ultrasound of the potential baby panda.
If the fetal tissue continues to develop, veterinarians at the zoo predict Mei Xiang could welcome a new panda in the next few days.
"Veterinarians first detected fetal tissue last week, and they have since noted developing skeletal structure and strong blood flow within Mei Xiang’s uterus. If the fetal tissue resorbs, her hormones will return to baseline levels and her behavior will return to normal," the press release said.
Mei Xiang was artificially inseminated back in March using semen from the zoo's male giant panda, Tian Tian. The panda gestational period ranges from 90 to 180 days, according to the National Zoo. The average panda pregnancy lasts 135 days.
“In the middle of a pandemic, this is a joyful moment we can all get excited about,” said Don Neiffer, chief veterinarian at the Smithsonian’s National Zoo who conducted the ultrasound, which was shared on YouTube. “We are optimistic that very shortly she may give birth to a healthy cub or cubs. We’re fortunate that Mei Xiang participated in the ultrasound allowing us to get sharp images and video. We’re watching her closely and welcome everyone to watch with us on the panda cams.”
Mei Xiang's fetail tissue was first discovered last week, which of course seems late in a pregnancy but is typical for pandas, according to the zoo. Despite the potential for welcoming a new panda in a matter of days, the zoo's veternarians cautioned that Mei could reabsorb the fetus or even have a miscarriage.
"Unlike humans, giant pandas experience a phenomenon referred to as delayed implantation. After fertilization, an embryo will not attach to the uterine wall until weeks or months later. It is not clear what causes the embryo to implant into the uterine wall. After implantation, the embryo grows exponentially. Veterinarians and the giant panda team have been conducting regular ultrasounds on Mei Xiang since July to track changes in her reproductive tract," the zoo explained.
If Mei Xiang does give birth soon, the baby panda would join their mom's previous three surviving cubs, but would have a long distance relationship with its siblings. The three cubs live in China, according to an agreement between China and the United States.