Kiangs run in Hoh Xil in Yushu Tibetan Autonomous Prefecture, northwest China's Qinghai Province, Dec. 2, 2016. Hol Xil has an average altitude of over 4,600 meters, making it an ideal habitat for Tibetan antelopes, kiangs and other animals. It was enlisted as one of the UNESCO's World Natural Heritages in July 2017. [Photo/Xinhua]

A Tibetan antelope is seen in a protective station in Hoh Xil in Yushu Tibetan Autonomous Prefecture, northwest China's Qinghai Province, Aug. 15, 2017. Hol Xil has an average altitude of over 4,600 meters, making it an ideal habitat for Tibetan antelopes, kiangs and other animals. It was enlisted as one of the UNESCO's World Natural Heritages in July 2017. [Photo/Xinhua]

Auxiliary police officer Xie Ancheng plays with a Tibetan antelope in Hoh Xil in Yushu Tibetan Autonomous Prefecture, northwest China's Qinghai Province, Aug. 15, 2017. Hol Xil has an average altitude of over 4,600 meters, making it an ideal habitat for Tibetan antelopes, kiangs and other animals. It was enlisted as one of the UNESCO's World Natural Heritages in July 2017. [Photo/Xinhua]

Auxiliary police officer Xie Ancheng feeds a Tibetan antelope in Hoh Xil in Yushu Tibetan Autonomous Prefecture, northwest China's Qinghai Province, Aug. 15, 2017. Hol Xil has an average altitude of over 4,600 meters, making it an ideal habitat for Tibetan antelopes, kiangs and other animals. It was enlisted as one of the UNESCO's World Natural Heritages in July 2017. [Photo/Xinhua]

Two kiangs are seen in Hoh Xil in Yushu Tibetan Autonomous Prefecture, northwest China's Qinghai Province, June 30, 2017. Hol Xil has an average altitude of over 4,600 meters, making it an ideal habitat for Tibetan antelopes, kiangs and other animals. It was enlisted as one of the UNESCO's World Natural Heritages in July 2017. [Photo/Xinhua]

Aerial photo taken on July 2, 2017 shows the landscape of Hoh Xil in Yushu Tibetan Autonomous Prefecture, northwest China's Qinghai Province. Hol Xil has an average altitude of over 4,600 meters, making it an ideal habitat for Tibetan antelopes, kiangs and other animals. It was enlisted as one of the UNESCO's World Natural Heritages in July 2017. [Photo/Xinhua]

A yak is seen in Hoh Xil in Yushu Tibetan Autonomous Prefecture, northwest China's Qinghai Province, Dec. 1, 2016. Hol Xil has an average altitude of over 4,600 meters, making it an ideal habitat for Tibetan antelopes, kiangs and other animals. It was enlisted as one of the UNESCO's World Natural Heritages in July 2017. [Photo/Xinhua]

Tibetan antelopes are seen in Hoh Xil in Yushu Tibetan Autonomous Prefecture, northwest China's Qinghai Province, Dec. 2, 2016. Hol Xil has an average altitude of over 4,600 meters, making it an ideal habitat for Tibetan antelopes, kiangs and other animals. It was enlisted as one of the UNESCO's World Natural Heritages in July 2017. [Photo/Xinhua]