One of the twin baby panda cubs born Saturday at Smithsonian's National Zoo in Washington, D.C. has died. We are sad to report that the smaller of the two panda cubs has died. We will continue to provide updates on social media w/ #Pandastory. — National Zoo (@NationalZoo) August 26, 2015 The twin cubs were the second and third cubs born to Mei Xiang, one of the zoo's two giant pandas, in the last two years, following the birth of Bao Bao in August 2013. Staff members had undertaken a method developed by breeders in China to care for the twins, switching them out regularly to ensure the mother gave attention to each cub and was not overwhelmed.