Tibetan antelope calves rescued by patrollers from the Hoh Xil National Nature Reserve in Northwest China's Qinghai Province on Wednesday. Photo: Snapshot of Sina Weibo

The mothers of 11 Tibetan antelope calves that were rescued on Wednesday by the Zhuonai Lake protection station at the world heritage site Hol Xil in Northwest China's Qinghai Province may have been killed by wolves and bears during migration, a Chinese animal expert said on Monday.

The 11 Tibetan antelope calves, rescued by patrollers from the Hoh Xil National Nature Reserve in Qinghai Province, are given milk three times a day, according to reports.

Tibetan antelope is a special deer-like species living on the Qinghai-Tibet Plateau that is given first-class state protection in China. 

Wu Xiaomin, a research fellow at the Shaanxi Institute of Zoology and Northwest Institute of Endangered Zoological Species, told the Global Times on Monday that these calves' mothers may have been killed and eaten by some wolves or bears. He noted that they are currently being fed milk as they are usually unable to eat grass until they are at least two months old. 

"Although the Tibetan antelopes migrate in herds, the adult Tibetan antelopes only take care of their own offspring. Those who lose their mothers are likely to die since no one will take care of them," Wu said, adding that only 30 percent to 40 percent of them survive to maturity.

The station has transferred four of the calves to a wildlife rescue center belonging to the Sonam Dargye protection station in Qinghai, and the remaining are scheduled to follow soon, according to reports. 

Most Tibetan antelope live in Qinghai, Southwest China's Tibet Autonomous Region and Northwest China's Xinjiang Uygur Autonomous Region. The mating period is generally between the end of November and December, and then the female Tibetan antelope begin migrating to Zhuonai Lake where they give birth after May. Around August, mothers take their offspring back to their original habitats. 

Wu said he is currently in Tibet to research the migration routes of Tibetan antelope, and hopes to find out the reason why these animals follow this routine every year. He noted that advanced technology including UAV detection, infrared cameras and satellite detection systems are used to track them. 

The number of Tibetan antelope in China sharply decreased from 200,000 to 20,000 due to illegal hunting in the 1980s, but has gradually increased to 300,000 in 2020 thanks for environmental conservation efforts and a ban on hunting, according to Wu.