U.S. Zoos See a Panda Boom America seems to be in the midst of a panda baby boom. The San Diego Zoo says giant panda Bai Yun appears to be carrying twins. Veterinarians there saw two fetuses on an ultrasound. This, after the giant panda at the National Zoo in Washington gave birth to a single cub earlier this month. And now the Atlanta Zoo is getting into the act: Officials there say its panda is also showing signs of being pregnant.