Officials say new mom doing well; 1 cub in incubator

When Bao Bao celebrated her second birthday on Sunday, she did not realize the gift from her mom, Mei Xiang, would be two siblings.

The Smithsonian's National Zoo announced on Saturday afternoon that giant panda Mei Xiang gave birth to a cub at 5:35 pm. The zoo's panda team had begun preparing for a birth when they saw Mei Xiang's water break at 4:32 pm and she was already having contractions.

Four and a half hours later, at 10:07 pm, Mei Xiang gave birth to a second cub.

Giant pandas give birth to twins almost 50 percent of the time, according to the zoo.

The zoo's panda team was able to retrieve one of the cubs and put it in an incubator, according to the zoo. But the team is not sure if the retrieved cub, which weighs 138 grams and appears healthy, is the first or second born.

The zoo said that Mei Xiang appears to be doing very well and has one cub in her possession. The panda team will alternately swap the cubs, allowing one to nurse and spend time with Mei Xiang while the other is being bottle-fed and kept warm in an incubator.

The zoo first announced on Aug 19 that it detected a 4-cm-long fetus on an ultrasound.

Excitement among panda lovers was triggered on Aug 10 when the zoo confirmed a secondary rise in Mei Xiang's progesterone levels, which suggested that she would either have a cub or experience the end of a pseudopregnancy.

Experts at the zoo expect Mei Xiang to spend almost all of her time in her den for the next two weeks with her newborn cub. The Giant Panda Habitat at the zoo has been closed since Aug 20 and will remain closed to provide quiet for Mei Xiang and her cub.

Reproductive scientists from the zoo and the Conservation Biology Institute artificially inseminated Mei Xiang on April 26 and 27. For the first time, scientists used semen collected from a giant panda named Hui Hui, who lives at the China Conservation and Research Center for the Giant Panda in Sichuan province and was determined to be one of the best genetic matches for Mei Xiang. A cub by Mei Xiang and Hui Hui would be genetically valuable, helping to preserve the genetic diversity of the panda population in human care, according to the zoo.

Scientists also used high-quality fresh semen collected from the zoo's male giant panda, Tian Tian, for the artificial insemination. DNA analysis will be used to determine the father of the cub.

Mei Xiang, whose name means "beautiful fragrance" in Mandarin, has given birth to two surviving cubs: Tai Shan and Bao Bao. Tai Shan was born July 9, 2005, and now lives in China. Bao Bao was born Aug 23, 2013. She will live at the zoo until she turns 4; at that time, she will also go to live in China and eventually enter the giant panda breeding program. Tai Shan and Bao Bao were both born as the result of artificial insemination.

chenweihua@chinadailyusa.com