When the grandfather and grandmother of Zhaxi Toinzhub died, they were treated to a sky burial according to their own will, like most Tibetans would do.

"I would certainly choose sky burial after my death, though I'm not a Buddhist believer," said Zhaxi Toinzhub, a young Tibetan in his 20s,  working at Lhasa, capital of southwest China's Tibet Autonomous Region.

Like the Han people's tribute to tombs, Tibetans still carry on ancient rituals like sky burials, displaying a timeless adherence to the old ways of life and death, unaffected by the changes that are rapidly affecting the rest of China.

The largest sky burial site at Drigung Til Monastery receives about ten bodies on average every day. The rituals carried out at the 900-year-old monastery are regarded auspicious.

The traditional Tibetan way for burial after death is to feed vultures with the bodies of the dead, the sacred creatures worshiped by the locals living at the roof of the world.

About 80 percent of Tibetans choose sky burial, as has been observed for thousands of years, said Basang Wangdu, director of the Nationality Research Institute of the Tibetan Academy of Social Sciences.

Sky burial is one of the three principal ways that Tibetans traditionally return their dead to the earth. The two others are cremation and water burial.

Sky burial is closely related with the Buddhism worshipped in the Himalayan region. Buddhists believe life recycles and advocate kindness and charity. The spirit of the dead is believed to leave the body the moment he dies and the dead should be fed to hungry vultures as a last token of charity.

The rituals are carried out by a special group of Tibetans -- sky burial operators.

65-year-old Celha Qoisang was the chief sky burial operator at Drigung Til Monastery. "I was totally exhausted everyday, but I'm  willing to live like this because sky burial is an important part in Tibetan life," Celha Qoisnag said.

He learned the techniques from his uncle and was engaged in the profession for about ten years. He usually dealt with one to up to 20 bodies every day and could adroitly dissect, smash, and feed the bodies to the vultures within two to three hours.

"I could only rest for one day every month, namely the 19th day each month in Tibetan calendar. And I usually spent the day reading sutras and praying for the dead," he said.

"According to a Tibetan Buddhist sutra, the divine in heaven get together on the 19th day every month and the mundane are not allowed to kill or let the divine smell blood," he said.

Every night, all the lamas would read sutras for the dead bodies staying overnight at the monastery, said Samdain, head of the democratic management committee of the Drigung Til Monastery.

The unique rituals have been respected by the central and regional governments. The regional government bans uninvited outsiders from participating in the rituals and photographs are extremely forbidden to show respect to the rituals and the dead.

Tibet has 1,075 sky burial sites and about 100 operators, according to figures from the regional civil affairs department.

Though the central government built a modern crematory in Tibet on Oct. 17 in 2000, it is not favored by Tibetans. The first Tibetan cremation was carried out on January 2, 2001.

Cremation is not popular among Tibetans due to thousands of years of tradition. Wood is so scarce in the mountainous areas of Tibet that, in the past, burning a corpse was reserved for people of stature .

Tibetans could choose their own burial way and sky burial is still widespread in Tibet, said Cedain Lhunzhub, head of Xishan Crematory in Tibet.

"In fact, burials are not that important after human beings' death, and we Tibetans prefer sky burial because it contains Tibetans' compassion and belief," Zhaxi Toinzhub said.