Tian Tian, a giant panda eats bamboo in the outdoor enclosure at Edinburgh Zoo ,Scotland April 12, 2016. The Royal Zoological Society of Scotland and Royal Botanic Garden Edinburgh will perform research into the complexity of the panda diet. [Photo/Agencies] 

Giant Panda twin cubs which were born on August 7, 2016, are seen in a breeding box inside their enclosure at Schoenbrunn Zoo in Vienna, Austria September 28, 2016. [Photo/Agencies] 

Photo taken on March 27 shows Xing Hui, the male panda, in the Pairi Daizi zoo in Belgium. [Photo/Xinhua]