Our ancestors penetrated each other skulls and we are just discovering what was the possible reasons of such procedure. Is called trepanation and is forming a hole in the skull of a person alive by cutting, scrapping or drilling layers of bone.
Trepanation in skulls is something that has been done across Earth, thousands of skulls with signals or trepanation have been discovered. The causes of these phenomena in skulls is widely unknown, some scientists suggest it was performed to treat pain. It have had the purpose of treating skull trauma or neurological deseases. The majority now concur trepanation was also used by ancient humans for ritual and cultural purposes.
Trepanation of the skull was practiced 7000 years ago in Greece, America and Africa, some areas of Polynesia and the Far East but it was abandoned by most cultures at the end of the Middle Ages. Some areas still carried the ritual in another places even in the 1900’s.
The evidence shows ancient humans performed skull trepanation to allow the passage of spirits in or out of our bodies, as a rite of initiation. In Russia, archeologist discovered skulls with a single hole in the head, several centimetres wide, showing evidence that’s was carved.