Analyses of cranial trauma in Neanderthal and modern human fossil remains

Abstract

Traumatic injuries in human skeletal remains provide crucial insights for reconstructing lifestyles, behaviours, and living environments of past humans. This cumulative dissertation aimed at furthering our understanding of cranial trauma in fossil remains of Neanderthals and Paleolithic modern humans using qualitative and quantitative approaches and addressed three major objectives. First, the cranial breakage patterns of two late Middle Pleistocene crania from the Apidima caves, Greece, were investigated to assess the timing of breakage. Second, the cranial trauma prevalence of Neanderthals was contrasted with that of early to mid-Upper Paleolithic humans to test the common perception that Neanderthals experienced exceptional high levels of trauma. Third, the cranial trauma prevalence throughout the entire Upper Paleolithic period was characterized, and it was investigated whether stressors likely associated with environmental changes after the Last Glacial Maximum (LGM) are reflected in different levels of trauma. To address the first objective, I employed virtual methods using CT scanning to differentiate fresh from dry bone breakage. Most fracture lines of the Apidima crania gave inconclusive results regarding the timing of breakage, suggesting that the criteria used for differentiation were insufficient or may not be readily applicable to fossil remains, especially when their depositional and taphonomic history is complex. To address the second and third objectives, I compiled a large dataset of Eurasian cranial fossil specimens (ca. 80–10 ka BP) through an extensive literature review and statistically compared trauma prevalence between samples using generalized linear mixed models (GLMMs). This approach allowed me to assess trauma prevalence in relation to multiple contextual variables and to account for differential preservation. Results indicated similar prevalence of cranial trauma in Neanderthals and Upper Paleolithic modern humans, contradicting previous suggestions of exceptionally high trauma rates in Neanderthals. In both taxa, trauma prevalence was higher for males than females, but results showed differences between the taxa in age-specific trauma prevalence. Trauma prevalence throughout the Upper Paleolithic period was similar to trauma rates found in Mesolithic and Neolithic samples. Moreover, males were slightly more often injured than females, and both sexes exhibited more trauma among the old age group. Environmental stressors likely associated with climatic changes after the LGM are not reflected in cranial trauma prevalence. The statistical approach using GLMMs provides a powerful alternative to conventional crude trauma frequencies for investigations of past trauma prevalence, especially when skeletal preservation is poor as in the fossil record.