Giant panda Bai Yun has been sequestered behind the scenes at the San Diego Zoo’s Panda Trek for some time now in order to provide her the solitude and environment most conducive to a successful pregnancy and cub-rearing experience. Surely many of you are wondering: is Bai Yun showing any signs of pregnancy? Until about a week ago, the answer was “no.” During most of the time since breeding in spring, she has been her normal, hungry, and active self.
We have been tracking many behavioral and physiological parameters that could give us a clue as to her pregnancy status, one of which is her appetite for bamboo. A decline in bamboo feeding is one of the first reliable behavioral indicators that something is happening with Bai Yun. When we see that she has begun leaving the leafy greens behind at a meal, we know that we are about three to four weeks from a potential birthing window.
Guess what? She started falling of her bamboo feeding late last week.
But hold on. Bamboo feeding generally gives us a broad idea of a birthing window, but it does not actually tell us if she is pregnant. Pseudopregnant females also experience similar changes in feeding patterns. So while we might have a picture of when a birth might occur, we cannot say for sure that a cub is on the way.
Bai Yun has been sitting for regular ultrasounds and thermo-imaging procedures, and we are collecting urine for hormone assays as well. I can tell you that her hormone profile is in full swing, and the ultrasounds have shown some positive changes indicating the hormones are having the desired effect on Bai Yun’s uterus. But again, all of this is consistent with pseudopregnant females as well.
As a result of these changes, we have given her access to her birthing den. In it, she has begun building her nest with bits of bamboo. She occasionally takes short naps in the den. She is showing us more positive pregnancy—and pseudopregnancy—behavior.
And so we wait. The days ahead will be telling. If we are able to visualize a fetus via ultrasound, we will know this is a true pregnancy. Keep your fingers crossed!
Suzanne Hall is a senior research technician for the San Diego Zoo Institute for Conservation Research. Read her previous post, The Bears Thank You.