URUMQI, Dec. 13 -- Chinese scientists are monitoring a group of wild yaks in the mountains of Xinjiang Uygur Autonomous Region using unmanned aircraft in order to collect more precise data on the endangered species.

The research program, carried out jointly by zoologists from Xinjiang's Altun Mountains nature reserve administration and Beijing Normal University, is aimed at finding out the exact number of wild yaks in the mountain wilderness and their living conditions in order to devise better preservation plans for the species.

An unmanned aerial vehicle flying a preset route over the mountains collected meteorological data and captured photos of the yaks and their habitats during four flights in November, said Zhang Xiang, deputy chief of the Altun Mountains national nature reserve administration.

He said the data are being analyzed and results of the survey would be published soon.

An estimated 10,000 wild yaks are believed to roam the Altun Mountains at an altitude of 3,000 to 6,000 meters, said Zhang.

He said the yaks are purebred and their habitats are undisturbed by human beings and other animals. "It's extremely difficult for field workers to access their habitats or track their activities."

Wild yaks are endemic to the highlands of western China, including Xinjiang, Tibet, Qinghai, Sichuan and Gansu. Rampant hunting has caused the wild yak population to shrink in past decades to between 30,000 and 50,000 at the end of last year.

The Altun Mountains nature reserve covers 45,000 square kilometers and has an average altitude of 4,500 meters. Lying at the juncture of Xinjiang, Tibet, Qinghai and Gansu, it is home to a wide variety of rare animals, including Tibetan wild donkeys and antelopes.