The Effects Of Cold Adaptation On The Growth And Development Of The Neandertal Cranial Base

Neandertals and modern humans possess very different craniofacial shapes. Some recent work has attributed these contrasting shapes specifically to differences in brain development, which are extrapolated to mean differences in cognitive function. However, this may not necessarily be the case. In this paper, it is suggested that a size increase in the cranial base and rapid cranial growth are due not to cognitive differences, but environmental factors, specifically Neandertal adaptation to cold. Adaptation to cold would not only explain the more rapid growth of the Neandertal cranium, but also elongation of the cranial base via elongation of the nasopharynx for maximizing air conditioning capabilities. The results indicate a closer relationship between Neandertals and cold adapted modern humans than either of these groups with the other two considered (early modern humans and warm-adapted modern humans). While all variables in the cranium are correlated to some degree, cranial base length is most strongly correlated with measures of facial projection. This indicates that, along with some other factors, elongation of the cranial base greatly affects projection of the face; this could be caused via elongation of the nasopharynx due to cold-adaptation. Cold adaptation early in Neandertal children would have prepared them for the harsh environment that they are born and raised in, allowing for a higher chance of survival in a harsher environment. Thus, environmental factors are considered a valid argument for the differing shapes and developmental trajectories of Neandertals and modern humans