A team of researchers with the German Archaeological Institute has found long, deliberate marks carved into ancient skulls found at the Göbekli Tepe dig site. In their paper published on the open access site Science Advances, the group describes the skull fragments they have been studying and offer some possible explanations for the markings they found.
Göbekli Tepe is the name given to an ancient temple in what is now southern Turkey—it was built approximately 9,000 years ago, during the Stone Age. Workers have been at the site for the past 20 years removing the soil covering the tall pieces of T-shaped limestone, some of which rise up to 18 feet from the ground. Thus far, researchers at the site report that it does not appear that the temple was used as living quarters, but was instead a temple where the locals gathered to perform rituals. One such ritual appears to have involved using human skulls—hundreds of them, broken into pieces, litter the areas between the limestone columns. These findings have caused researchers to label the site as evidence of one of the earliest skull cults. In this new effort, the researchers report that some of the skull pieces have been found to have lines cut into them.
The team determined that the skull fragments they found with the unique marks on them belonged to just three individuals—each had deep straight-line grooves carved into the bone and one of them also had a hole drilled through its top. The grooves were found to measure between 0.2 and 4 millimeters deep and were clearly made by a person using stone tools, rather than by another animal or other natural process. Also, it was determined that the grooves were made after the person had died—there was no bone growth suggesting natural repair. Also, it appeared likely that the grooves had been made shortly after the person had died, while the bone was still relatively elastic.


Because it is not clear why the grooves appeared only on three skulls, the researchers were left to generate theories—they believe one of the likeliest possibilities is that the grooves were made to hold cords in place while the skull was hoisted onto a pole using the drilled hole—possibly as a way to scare off enemies.