Photo taken on Jan 17, 2016 shows a giant panda playing at Chengdu Research Base of Giant Panda Breeding in Chengdu, southwest China’s Sichuan province. [Photo/Xinhua]

Photo taken on May 6, 2016 shows a giant panda cub at Chengdu Research Base of Giant Panda Breeding in Chengdu, southwest China’s Sichuan province. [Photo/Xinhua]

Giant pandas are seen at Chengdu Research Base of Giant Panda Breeding in Chengdu, southwest China’s Sichuan province, Sept. 9, 2016. [Photo/Xinhua]

A giant panda is seen in Chengdu, southwest China’s Sichuan province, May 11, 2016. [Photo/Xinhua]

A giant panda is seen in Chengdu, southwest China’s Sichuan province, May 11, 2016.

Giant panda “Panpan” is seen in Chengdu, southwest China’s Sichuan province, July 15, 2016.[Photo/Xinhua]

A giant panda is released in Ya’an City, southwest China’s Sichuan province, Oct 20, 2016.[Photo/Xinhua]

Two giant pandas mate naturally in Ya’an City, southwest China’s Sichuan province, April 14, 2016. [Photo/Xinhua]