|MadSci Network: Evolution|
Mark: I think several other contributors have already hinted at the evolutionary purpose of head and facial hair, so I will just summarize a few thoughts. First, the hair on the top of our heads is likely there to provide protection from cancer-causing ultraviolet rays and to help moderate blood temperature in extremely cold or hot weather. Although there are many men who lose their hair in their 40s, 50s, etc., remember that several thousand years ago, a 50 year-old bald man would have been considered very, very old. With regard to hair cuts, we would first have to assume that keeping hair short would be a primary consideration, although I doubt there were many Cher Bono-types 35,000 years ago. If we are talking about a tool-using people, hair could be cut with a sharp stone blade, as you suggest, but just banging the hair between two rocks would have been enough to sever it; pre-tool people could also have chewed their hair and beards off. I suppose it's possible that pre-stone tool people could even have tied long hair back with a short length of vine! Aside from biological functions, I think hair has probably always had some "cultural" display function-- think about the evolutionary advantage that an early Homo Sapiens Elvis would have had! Dan Pratt
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