Last night there was to do at the zoo. I had to be there for giant panda training (I'm a volunteer behavior watcher, tracking panda behavior twice a month or so) and some event had things blocked up all around the place with lots of police because some mucky-mucky was supposed to be in attendance. I got in before the checkpoints were set up, but a lot of other people got tied up. (Actually, I was a bit worried that my car would end up being towed or something.) It turns out it was Smithsonian Resident Associates Night; no idea whose appearance required such an extensive shutdown, but whatever.
I thought the training was going to be a refresher on the ethogram, behaviors and so forth for the longitudinal study that I've been volunteering on since Mei and Tian arrived in D.C., but most of it was about panda pregnancy. Mei Xiang probably isn't preggers, but panda reproduction is so bizarre that its hard to say for sure until a cub does or doesn't appear. Right now the plan is limited watches in the morning to help train newcomers to the program; as the signs of pregnancy/psuedopregnancy progress, then we'll move up to 24-hour watches.
Not only to pandas have a very short window of opportunity for mating each year (just a day or two), it's impossible to know exactly when a birth might occur afterwards. A fertilized panda embryo can have implantation delayed for 30 to 50 days after mating, and only after that do you have the normal gestation period. So the pregnancy watch is likely to start in early July and run until September with a possible birth or end of pseudopregnancy at some point during then.
The other thing that makes pregnancy difficult to diagnose in pandas is pseudopregnancy, which means that the hormone levels in the bear go up to pregnancy levels and pregnancy-related activities (i.e., nest building and cradling objects) occur. Also ultrasounds aren't reliable because the cub (even at full term) is fairly tiny -- about the size of a stick of butter.
So, anyway, we got to see videos of panda births and of pregnancy/pseudopregnancy behaviors, which I guess is only fair because the last big training session was all about mating behavior and we got to watch tons of panda porn... I guess there's nothing else that can be said about that.