Every year, tens of thousands of pregnant Tibetan antelopes start their migration to Hoh Xil in around May to give birth and leave with their offspring in late July.
Aerial photo taken on Aug. 29, 2018 shows a view of Tongtian River at the Sanjiangyuan National Park in northwest China s Qinghai Province. Sanjiangyuan, meaning the "source of three rivers," is home to the headwaters of the Yangtze, Yellow and Lancang rivers. The ecological system has been steadily improving in recent years in the Sanjiangyuan National Park, making it a habitat of an increasing number of wild animals.