Eleven months after the zoo sent its three wildly popular pandas — Mei Xiang, Tian Tian and their cub Xiao Qi Ji — back to China, a new pair of bears arrived in the United States on Tuesday.

The National Zoo’s three giant pandas, Mei Xiang, Tian Tian and their cub Xiao Qi Ji. on Wednesday began their long trip to China, leaving behind an empty panda exhibit with no certainty that ...