Head form and climatic stress



Empiric evidence indicates that the general distribution of the cephalic index is explicable in terms of climatic adaptation. Based on a sample of 339 populations, the magnitude of the index is statistically different between zones of predominantly dry heat, wet heat, wet cold and dry cold. There is an inverse relationship between the mean cephalic index and temperature. It is argued that the occupation of cold climates is one of the circumstances increasing the frequency of brachycephaly through time.