|MadSci Network: Anatomy|
"Hmmmm", I mumbled while stroking my moustache, "just what purpose does this thing serve?" It keeps my nasal secretions from reaching my mouth, it collects cookie crumbs, some of which would be a sin to waste, it provides a reference point as to where to place my thumb and index finger when pondering great queries of the universe, such as this one.
Body hair is a characteristic feature of land-based mammals. Over millenia changes in distribution and characteristics of body hair have occurred. This is evident not only between the males and females of the species, but also differences among and within ethnic groups. For example, the difference between Southern Italians and Greeks and the aboriginal "native" groups in North and South America. Although the density and distribution of body hair has changed, the hair on the head and face has become more prevalent over the past 5 - 8,000 years.
The function of body/facial hair in mammals is to provide warmth and physical protection (from the elements, insects or other 'minor' predators). Although modern humans have less facial hair in general, the purpose of a beard and/or moustache is generally ornamental/decorative and a personal preference. If you notice, the males of some animal species are more decorated than others, brighter colored feathers, hair in certain areas. In humans, the reason that males have more facial hair is a predominence of the hormone "testosterone". This is what what makes a man a man (and configures the brain to reject the notion of reading enclosed instructions before assembling an intricate power tool accessory). Females do have small amounts of testosterone produced by the ovaries, but the overwhelming amount of the hormone "estrogen" determines a more "feminine" appearance, including less body hair and little to no facial hair.
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