Photo shows newly arrived giant panda Yuan Yuan sitting in his enclosure at the Schonbrunn Zoo in Vienna, Austria on Wednesday, April 17, 2019. The 20-year-old male panda left China for Austria on Tuesday for a four-year collaborative research project. (Photo/Agencies)

Photo shows newly arrived male panda Yuan Yuan walking in his enclosure at the Schonbrunn Zoo in Vienna, Austria on Wednesday, April 17, 2019. (Photo/Agencies)