Giant panda cub turns 1 month old Time flies, and one of Washington's most-celebrated new residents has passed a milestone: the giant panda cub at the National Zoo turned 4 weeks old Friday and appears to be thriving. She is "growing exponentially," the zoo said, and is nearly as round as she is long. The cub has apparently seen nothing of the adoration provoked by her birth on Aug. 23. In fact, it may be a while before her eyes even open, the zoo said. That usually comes between 40 and 60 days after birth. 16, her first veterinary exam gave her a clean bill of health. Her mother, Mei Xiang, left her temporarily, and zoo staff members checked her out. She weighed a little less than two pounds and was 101 / 2 inches long.