Archaeologists have made a remarkable find in a 12,000-year-old stone temple known as Göbekli Tepe, in southeastern Turkey, uncovering the remains of human skulls that were stripped of their flesh and carved with deep, straight grooves running front to back.
     The carvings represent the first evidence of skull decoration in the archaeological record of the region. "This is completely new, and we don't have a model to go on," says Gary Rollefson, an archaeologist at Whitman College in Walla Walla, Washington, who was not involved with the work. "The purpose of the carvings is unclear", he says, "But they may have been part of an ancient religious practice. There seems to be a focus on ritual reuse after decapitation."
     The site boasts multiple enclosures with tall, T-shaped pillars surrounded by rings of stones, many carved with reliefs. Such structures are unique for humans at this time. When excavations at the site began in the mid-1990s, archaeologists expected to find human burials. Instead, they found animal bones by the tens of thousands. Mixed in were about 700 fragments of human bone (more than half of them are from skulls), scattered throughout a loose fill of stones and gravel.
     In a paper published in Science Advances, Gresky and her co-authors describe 3 large skull fragments, each about the size of a hand. Cut marks on the bones suggest that someone removed the flesh and then carved bone with deep, straight grooves running front to back. One skull had a hole drilled into it, although only half of the hole was preserved. Heads - missing or decapitated - are also represented in the site's stone artwork. The heads of some stone statues were deliberately removed or knocked off; archaeologists think one statue, which they dubbed the 'Gift-bearer,' depicts a kneeling figure holding a human head.
     The attention to skulls is part of a long tradition, although it's the first instance in that region."This treatment of fragments is awfully unique. I don't know of any other skulls where they've been carved or drilled," Rollefson says. "They're deep incisions, but not nicely done. Someone wanted to make a cut, but not in a decorative way," Gresky says. "It could be to mark them as different, or to fix decorative elements, or to hang the skulls somewhere."
     Whatever their purpose, the carvings seem to mark the skulls as outliers: Dozens of other skull fragments have been found at Göbekli Tepe with no sign of carving or cutting. That suggests these skulls were singled out after their owners' deaths for some reason. "They are really special, these three individuals," Gresky says. The skulls might have been displayed as part of ancestor worship, or as trophies to show off the remains of dead enemies."
     Michelle Bonogofsky, a visiting scholar at the University of California, Berkeley's Archaeological Research Facility, argues that there's not enough evidence to say what the skulls were for - and may never be, she says: "This is thousands of years before writing, so you can't really know. The marks do appear to be intentional, but what the intention was I can't say."

Edited from Science Magazine (28 June 2017)