Now that 20-month-old giant panda cub Bao Bao is living apart from her mother, Mei Xiang, the National Zoo’s favorite activity is approaching. It’ll be panda breeding time in the next few weeks, and the Smithsonian is making it well known that its scientists are ready to make another little tourist attraction. In fact, the necessary supplies just arrived Monday.
Caitlin Burrell, one of the zoo’s research scientists, returned to Washington yesterday from China, bringing with her a high-tech canister holding ten vials of frozen sperm from a male panda at a conservation center in Sichuan Province. If Mei Xiang goes into estrus, Burrell and the rest of the zoo’s panda team will attempt to artificially inseminate the bear with one of the samples. The zoo says adult female pandas enter estrus 45 to 50 days after being separated from their most recent offspring—Bao Bao, born in August 2013, moved out on March 1.
After picking up the panda sperm samples, each of which contains one-quarter of one milliliter, Burrell took a commercial flight from Chengdu, China to San Francisco, followed by the final leg to Dulles International Airport. The canister, which kept the sperm straws frozen at -196 degrees Celsius, flew in a storage compartment in the main cabin.
“It’s groundbreaking for giant panda reproduction to import semen from China for breeding in the United States,” Dennis Kelly, the zoo’s director, says in a press release.
But while the National Zoo is locked and loaded for the day Mei Xiang begins her 24-to-72 hour estrus, some might wonder what is to become of its resident adult male giant panda, Tian Tian. While samples collected from Tian Tian helped create Bao Bao and the zoo’s previous surviving panda cub, Tai Shan, his days as a breeder appear to be finished. Hui Hui, born in 2005 (eight years younger than Tian Tian), was selected because a cub sired from his sperm is deemed far more “genetically valuable” to the overall giant panda population than yet another cub with Tian Tian’s genetic material. Hui Hui has not sired any cubs yet, says zoo spokeswoman Devin Murphy.
One could also argue that in bringing in relief for Tian Tian, the zoo is sparing the old bear another round of sexual embarrassment. While some giant pandas are full of energy, Tian Tian has a documented history as a “clueless breeder with flawed technique,” so much so that when Bao Bao was born, the zoo borrowed a page from Maury Povich to determine if Tian Tian or another donor bear had provided the sperm that created the newborn.