Mei Xiang. (Photo by Daniel Reidel)

Call it an instance of right place, wrong time. Our two romantic leads were certainly feeling the heat, but there was no natural breeding for giant pandas Mei Xiang and Tian Tian this season.

That doesn’t mean Mei Xiang won’t get pregnant, though. On Thursday, a team of reproductive scientists, veterinarians, and panda keepers at the Smithsonian’s National Zoo performed two rounds of artificial inseminations on the 18-year-old panda using Tian Tian’s semen.

Because female pandas can only become pregnant during such a short period of time annually—between one and three days—the National Zoo carefully monitors Mei Xiang’s hormones and behavior to determine when she’s ovulating.

The path of artificial insemination is not new for this panda family. Bei Bei, Bao Bao, and Butterstick, all three of Mei Xiang and Tian Tian’s kids, were all the result of the procedure.

That’s because Tian Tian and Mei Xiang are what The New Yorker calls “reproductively incompetent.” While they know they want to breed, they can’t quite figure out how to do the deed. This has been happening since 2000.

While the pandas indicated they were interested in breeding this year, they did so “at incongruent times,” according to the National Zoo. Like so many couples, they just couldn’t get the timing right.

Tian Tian gets playful and restless, spending his days playing in water, marking areas with his scent and bleating at Mei Xiang. He’s been feeling this way since late March, and scientists call it “full rut.”

When Mei Xiang responds with a chirp rather than a moan to Tian Tian’s vocalizations, zookeepers know she’s hit the estrus stage (the scientific term for being in heat). She too enjoys water play and feels restless in estrus. Earlier this week, keepers determined that she was about to hit peak estrus.

Giant panda pregnancies are about three to six months-long. But Mei Xiang could also be pseduopregnant, a condition where her hormones and behavior reflect that she’s got a bun in the oven even though she doesn’t. Only an ultrasound will tell for sure.