A frontal view of Cranium 17 showing the position of the traumatic events T1 (inferior) and T2 (superior). Credit: Javier Trueba/Madrid Scientific Films
The Spanish archeologist who helped piece together possibly the earliest case of murder in human history has published another study that demonstrates evidence of nine additional murders in the same location.
Over the last 30 years, archeologists have recovered more than 2,000 bone fragments representing 29 individuals from the archeological site Sima de los Huesos in northern Spain. The bones, located deep within an underground cave system, represent the Homo heidelbergensis species of humans that walked the Earth about 430,000 years ago, during the Middle Pleistocene.
“So far, we have 20 individuals represented by their skulls and jaws of the 29 we estimate on the basis of the dentition,” said Nohemi Sala, a researcher at the Centro Nacional de Investigación sobre la Evolución Humana (CENIEH) who regularly excavates the site and is the lead author of the newest study. “This huge number of specimens has made studying the forensic taphonomy of a fossil population possible, something that would be unthinkable outside the walls of this chamber.”
In 2015, Sala and colleagues pieced together a nearly complete skull—Cranium 17—from 52 cranial fragments recovered during excavations at Sima de los Huesos over two decades. According to the study, the skull showed two penetrating lesions on the frontal bone, above the left eye. Relying on modern forensic techniques, such as contour and trajectory analysis of the traumas, Sala and colleagues demonstrated that both fractures were likely produced by two separate impacts by the same object, with slightly different trajectories around the time of the individual's death.
According to the authors, the injuries are unlikely to be the result of an accidental fall down the vertical shaft. Rather, the type of fracture, their location, and that they appear to have been produced by two blows with the same object led the team to interpret them as the result of an act of lethal aggression—even possibly the earliest case of murder in human history.
"By looking at points such as marks and fractures in the fossils, we can decipher processes, as though we were conducting an autopsy," said Sala in her newest study, which reveals additional information on the found skull bones, including time and type of injury.
Previously it was determined that 17 of 20 specimens with recovered skulls experienced non-fatal blunt force trauma that had time to heal before death. But now, in the new study published in PLOS ONE, Sala and her team have verified the presence of a new individual with perimortem cranial fractures, bringing the total to nine individuals with evidence of cranial traumas that could have been lethal.
Strikingly, of the nine individuals with perimortem traumas, six had penetrating fractures in the left nuchal region.
“This pattern is so recurrent that it leaves little room for interpretation. The location is not what would be expected for accidental traumas, and is more compatible with intentional lesions, so these injuries are interpreted as possible cases of violence, just as with skull 17,” the research team explains.
The archeologists also documented postmortem modifications, demonstrating that the bones show fracturing due to sediment pressure and precipitation of minerals—characteristics only associated with cave environments. The team did not record any marks attesting to long-distance transport of the remains.
“We can interpret this to mean that the skeletons arrived at the cave complete, and shortly after death," said Sala.
Based on previous research in addition to these new findings, the researchers are confident humans were likely responsible for the accumulation of bodies in the Sima de los Huesos, suggesting the site represents early evidence of funerary behavior.