History and development[edit]
The Tibetan sky-burials appear to have evolved from ancient practices of defleshing corpses as discovered in archeological finds in the region.[4] These practices most likely came out of practical considerations,[5][6][7] but they could also be related to more ceremonial practices similar to the suspected sky burial evidence found at Göbekli Tepe (11,500 years before present) and Stonehenge (4,500 years BP).[citation needed] Most of Tibet is above the tree line, and the scarcity of timber makes cremation economically unfeasible. Additionally, subsurface interment is difficult since the active layer is not more than a few centimeters deep, with solid rock or permafrost beneath the surface.
The customs are first recorded in an indigenous 12th-century Buddhist treatise, which is colloquially known as the Book of the Dead (Bardo Thodol).[8] Tibetan tantricism appears to have influenced the procedure.[9][10] The body is cut up according to instructions given by a lama or adept.[11]