Prehistoric humans may have practiced brain surgery on cows

Humans have been performing brain surgery—or at least drilling holes in one anothers’ skulls—for thousands of years. But how did they get their practice? A new study analyzing an exquisitely bored hole in the skull of a 5000-year-old cow (above) suggests they may have honed their skills on animals.

The bovine cranium in question was found in Vendée, France, a Neolithic site that was a trade hub for salt and cattle between 3400 and 3000 B.C.E. Scientists originally thought the cranial hole came from a traumatic blow by another cow, but others suspected a human hand at work.

To find out whether early human surgeons were responsible, scientists compared the hole in the cow’s skull to holes in two human skulls from France dated to the same period. It was clear from the long straight lacerations that the human skulls had undergone some sort of primitive brain surgery. Using a combination of powerful microscopes, hand lenses, and 3D reconstructions, the researchers looked for telltale signs of deliberate cutting on the cow skull. Long, parallel marks surrounding the hole and traces of scraping motions matched those found around the openings in the human skulls, leading researchers to conclude that the cow's gape came courtesy of human surgeons, they reveal today in Scientific Reports .

In addition to ruling out an untimely goring, the researchers also excluded infection, cancer, erosion, and gnawing by animals as the cause thanks to the uniform shape of the hole. That means the bovine skull is the earliest evidence of surgical experimentation on an animal. What remains to be seen, researchers say, is whether the surgery was done to save the cow’s life or whether it was used by aspiring surgeons for perfecting delicate techniques before operating on fellow humans.