Mei Xiang, the female panda who lives at the Smithsonian National Zoo, gave birth today. Above is a screen shot from the Zoo's Panda Cam, showing the baby shortly after birth.
Why should you care about this not-quite-yet-but-soon-to-be adorable baby animal more than you care about any other adorable baby animal? Because the scientific oddities of panda reproduction make its story very interesting.
First, it's incredibly difficult for pandas to get knocked up. They're only fertile once a year and have trouble successfully mating in captivity. Mei Xiang was artificially inseminated with the sperm of two different male pandas back in March. All of Mei Xiang's cubs have been conceived this way, but the artificial inseminations don't always work. She gave birth once in 2005 to Tai Shan who now lives in China. It was another 7 years before a second pregnancy took, but the unnamed cub only lived for six days.
Second, you can't tell whether or not pandas are pregnant until there either is or isn't a baby panda.
They go through the same symptoms and physical changes either way and nobody even knows exactly how long the panda gestation period is.
Plus, they're notoriously difficult to successfully ultrasound. In fact, Mei Xiang's last ultrasound on August 5 showed no sign of a fetus.
Basically, panda reproduction is weird.
So, break out the bubbly for this new, little cub with a bit more enthusiasm than might be applied to, say, a litter of rabbits.