Image of panda bear cub at its first exam from the National Zoo. Exciting news from the Smithsonian National Zoological Park! Mei, a giant panda bear at the zoo has given birth to a cub weighing in at 137 grams (~4.83 ounces)-too cute!! DNA tests will determine the sex as well as the paternity of the panda cub, which is either Tian Tian from the National Zoo or Gao Gao from the San Diego Zoo. You can follow the Twitter feed from the Smithsonian here: #cubwatch in additon to checking out the live panda cam at the zoo.