Wild yaks are seen at the Haltent grassland in the Kazak Autonomous County of Aksay, northwest China's Gansu Province, Dec. 23, 2020.Photo:Xinhua

Tibetan gazelles forage at the Haltent grassland in the Kazak Autonomous County of Aksay, northwest China's Gansu Province, Dec. 23, 2020.Photo:Xinhua

Wild yaks are seen at the Haltent grassland in the Kazak Autonomous County of Aksay, northwest China's Gansu Province, Dec. 23, 2020.Photo:Xinhua

Wild yaks are seen at the Haltent grassland in the Kazak Autonomous County of Aksay, northwest China's Gansu Province, Dec. 23, 2020.Photo:Xinhua

A wild yak is seen at the Haltent grassland in the Kazak Autonomous County of Aksay, northwest China's Gansu Province, Dec. 23, 2020.Photo:Xinhua

Wild yaks are seen at the Haltent grassland in the Kazak Autonomous County of Aksay, northwest China's Gansu Province, Dec. 23, 2020.Photo:Xinhua