Initially this morning there was no real interest, but enclosure swapping was implemented and the interest level quickly increased. It took about 38 minutes for Gao and Bai to coordinate their positions, but the actual copulation lasted nearly 2 minutes. It only requires one mating, so this morning’s interaction just increases the likelihood of a future pregnancy. Whether there will be another mating today will depend on the pandas, but the amount of energy already expended by Gao Gao may be the determining factor.
Now, to anticipate some of your questions:
Panda gestation is about 45 days, but they can delay implantation for up to 6 months or longer. We don’t understand how this works, but it has the advantage of having cubs born later in the year when food is more plentiful for the mother. This delay is common to other bears, as well as rabbits and other species.
Determining panda pregnancy is challenging, since females can go into pseudo pregnancies that behaviorally and hormonally mimic a real pregnancy. Ultrasound and thermal imaging are employed, but it can still be difficult to locate a tiny fetus in the body of a 200+ pound bear with a gut full of bamboo.
Once mating season is concluded, the pandas may once again be rotated on and off exhibit, but the timing of this is determined by the animal care staff and research needs – and, of course, whether we are on birth watch.
Keep your fingers crossed for our wonderful mom as we begin the careful watching- and-waiting phase of the panda breeding process.
Ellie Rosenbaum is a panda narrator at the San Diego Zoo.