In Tibet, the practice of offering recently deceased humans to birds of prey is known as giving charity to the birds. Most of Tibet is Buddhist, and Buddhists believe in reincarnation so there is no need for the body after the soul has departed. The offering of the corpse to the birds is indeed charity for them because it is food that they do not have to hunt for on their own. In Buddhist tradition, it may also show respect and kindness for other living things. It is also very practical in Tibet where the ground is hard and rocky, making grave-digging very difficult, and in some mountainous regions, impossible due to a permanent layer of frozen ground — known as permafrost.
The actual practice involving cutting or hacking the body is performed in a solemn ceremony by monks. In some populous areas, sometimes the vultures need to be encouraged to eat, but in other less populous areas, the vultures participate as one would expect.
In India, the Parsi practice “sky burials.” The Parsi’s are a tiny minority worldwide, numbering only about 100,000, the majority of whom live in India. Most historians believe the Paris emigrated from Persia to parts of the Indian subcontinent around 1,000 A.D. bringing with them their Zoroastrian religion. In the Zoroastrian tradition, a dead body is considered unclean, and offering the body to birds of prey was a way to avoid contamination of the earth (through in ground burial) or fire (by burning the corpse). To avoid contaminating earth or fire, the corpses are placed on round, flat, towers, where birds of prey can easily land to feed on the bodies, and the sun can assist in the decomposition of the body. The towers are referred to in the West as “towers of silence” — a term given to the towers by a British colonial translator in 1832.
For decades vultures in India would consume a corpse in minutes, making sky burials there very effective in disposing of human corpses, but the vulture population in India has fallen by 99.9% since the early 1990’s due to diclofenac poisoning in vultures. This poisoning occurs by the vultures consume dead livestock, which livestock have been given diclofenac, which is an anti–inflammatory and anti-fever drug. The India government has banned livestock use of diclofenac to try to restore the vulture community.
The benefits of sky burials are its economics and its environmental friendliness. It is significantly less expensive to “sky bury” the corpse than to inter it, and it uses significantly less land and equipment. The detriments are that once the corpse is eaten, there is nothing left from which to obtain DNA at some point in the future, unless some bone might be saved and kept for future DNA matters. DNA from a body might be useful in the future for identifying a body or establishing paternity, or finding a bone marrow match.
Sky burials are one of those religious traditions that is not widely-known in the West. A very popular book of fiction (a love story) by the name Sky Burials was published in 2006. Bringing the term into wider usage.