Buddhism fills in every aspect of Tibetan people’s lives, and a Buddhist’s life is about giving. A Tibetan Buddhist would live a life of giving, even at his or her final moment by dedicating the flesh and bones to the nature. Sky burial and water burial are two dominant burial ceremonies in Tibetan areas, especially sky burial, as it is a cultural label for the Tibetan identification.
In Tibetan Buddhism, it is believed that after one’s current life, the soul will leave the body and be at an uncertain existence until it rejoin one of the six realms, and hence the earthly body would be nothing but flesh and bones and it should be returned to the nature, and to use it to feed other animals can maximize its usefulness and charity. While water burial offers the body to creatures in the river, sky burial is a ceremony that gives the corpse to vultures, which is considered a noble animal and able to make the reincarnation easier.
Sky burial has not been a secretive ritual, as anyone can watch at their will, and I personally had the experience to witness one. To the contrast of what many may believe, the ceremony actually took place in a casual and light atmosphere, as the body of the deceased was divided in a relaxed fashion, and once the rogyapas (people who break the body) placed the pieces and left, the vultures took everything, while everyone at the scene chanting mantra to pray for a easy transition for the deceased.
At a time, sky burial was strictly banned throughout Tibet, Qinghai, Sichuan, and Yunnan in concern of that the ceremony may cover up some crimes, and currently the government allow the ceremony again under regulations. If you get the opportunity to witness a sky burial, there is no need to take it as too extraordinarily, as it is simply a part of a culture, and just remember to be respectful, and pray for the dead to have a good belonging in the next life.