He and his colleague argue that goring by another animal would have produced fracturing in and around the wound — characteristics absent from the cranium. They also negate the possibilities that the hole was produced by humans seeking bone for tools or by natural causes, such as a tumor or even intrusion by insects.
The researchers instead argue that the almost square shape of the hole, the lack of any marks indicating pressure by an exterior force, and the presence of cut-marks around the hole all suggest that the injury resulted from a surgery. Since there is no evidence for healing, they believe that the procedure was performed on a dead cow, or that the cow did not survive.
The location of the hole interestingly matches where trepanation procedures typically occur on humans.
Froment explained, "This very place on the skull does not cause internal hemorrhage because there is no vein sinus under the bone in that place."
Ramirez Rozzi told Seeker that evidence for trepanation is found all over the world and across multiple time periods. Froment clarified that the most ancient trephined human skull was found in the Ukraine and is dated to about 7,300–6,200 BC. In France, the most ancient trephined human skull is about 7,000 years old, he added.
The researchers previously suspected that a Neolithic wild boar also underwent trepanation, but they could not directly study that particular skull.
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Although their paper presents a few different scenarios explaining the bone surgery, both authors favor the idea that Neolithic people practiced surgical procedures on animals before applying them to humans.
Ramirez Rozzi said, "You see a great deal of expertise in human skull trepanation, and the question has always been, 'How could those who carried out these procedures have had the knowledge to do them so perfectly?' They certainly must have practiced before performing surgery on live humans."
He then admitted, "This is a supposition, but it follows logical reasoning."
It will be challenging to identify the remains for other animals that might have also been used during possible practice surgeries.
As Ramirez Rozzi said, "Unfortunately skulls showing this practice would likely be lost among many other skulls. Hopefully more attention will be paid to the matter in future."