Newly arrived giant panda Yuan Yuan sits 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. (Photos: China Plus)

Newly arrived male panda Yuan Yuan walks in his enclosure at the Schonbrunn Zoo in Vienna, Austria on Wednesday, April 17, 2019.