Four captive-bred Tibetan antelopes gave birth to four calves in northwest China's Tibetan Antelope Rescue Center in July, said an official from a nature reserve located near Hol Xil Lake in Qinghai Province on Tuesday.

The endangered Tibetan antelope, which is under first-class state protection in China, largely inhabits northwest China's Qinghai-Tibet Plateau. Pregnant Tibetan antelopes migrate to Hol Xil Lake every June and July to give birth.

Xiao Penghu, the deputy chief of the Hoh Xil National Nature Reserve Administration, said that the four calves were born between July 10 and 16.

"This is the fifth time that captive-bred Tibetan antelopes have given birth at our center," Xiao said.

The world's first captive-bred Tibetan antelope successfully gave birth at the center in 2006.

The center is situated in the Hoh Xil Nature Reserve, which is located in the Tibetan Autonomous Prefecture of Yushu, Qinghai Province.

According to Xiao, 339 wild animals, including 224 Tibetan antelopes have been bred, nursed and given medical treatment at the center since its establishment in 2003.

"Most of the wild animals were set free after their recovery," Xiao said. "We still have about 30 Tibetan antelopes in our center," he said.

Perched at an altitude of 4,500 meters, the Hoh Xil reserve contains the largest area of uninhabited land in China.

The Qinghai-Tibet Plateau used to be home to millions of Tibetan antelopes. However, overhunting and the destruction of their natural habitat has decimated the population.

Poachers hunt the antelopes for their hides, as they can be sold and made into shahtoosh shawls, a luxury item that requires three to five Tibetan antelope skins to make just one shawl.

Since 1979, the Tibetan antelope has been recognized as an endangered species and protected under the Convention on International Trade in Endangered Species.

The Tibetan antelope was selected as one of the five mascots of the 2008 Beijing Olympic Games.

According to Xiao, the number of Tibetan antelopes living in the Hoh Xil region has increased from around 50,000 in 2006 to more than 60,000 today.