Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Human body hair

  1. Nov 22, 2015 #1
    Humans lost body hair in order to lose heat more efficiently according to this article.
    http://www.independent.co.uk/news/s...s-from-overheating-as-we-evolved-8498623.html

    So , some humans moved out of Africa and into the cold regions of the northern hemisphere , why didn't they grow their body hair back?

    This article gives a number of explanations as to why humans might have lost their body hair but the 'losing heat ' hypothesis appears to be most reasonable.
    http://www.scientificamerican.com/article/latest-theory-human-body-hair/
     
    Last edited: Nov 22, 2015
  2. jcsd
  3. Nov 22, 2015 #2

    Evo

    User Avatar

    Staff: Mentor

    The last ice age occured very rapidly, within a decade or even just a few years. Not enough time to adjust.

    http://geology.utah.gov/map-pub/sur.../ice-ages-what-are-they-and-what-causes-them/
     
  4. Nov 23, 2015 #3
    http://humanorigins.si.edu/modern-humans-reach-europe

    Humans moved to Europe little over 40,000 years ago , they had enough time to evolve white skin for vitamin D production I think ,but why not body hair? I guess natural selection did not happen based on body hair because they started using animal skin for protection very early on and hence there was no selective pressure on this aspect.
     
  5. Dec 2, 2015 #4
    Human ancestors lost their body hair when they began to live in hotter climates as they moved out of forest ecosystems and into plains ecosystems. Dense fur became a liability when it came to keeping cool rather than a benefit. The dry heat and lack of shade on the plains made it preferable to use evaporative cooling by sweating to regulate temperature rather than to use fur and avoid the hot sun.

    From there, it was carried forward by sexual selection. Facial hair in men enhances the appearance of a broad jawline, scalp hair quality is an indicator of overall health, having less body hair overall allows figure and muscle tone to be more clearly-defined, and having certain amounts of body hair in the right places signifies an optimal mix of developmental and reproductive hormones (ie that a potential mating partner would be more likely to be receptive to advances and more likely to reproduce successfully).

    Basically, it wasn't due to migrations to Europe or the development of agriculture, anatomically modern humans lost their body hair well before humans were behaviorally modern.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Human body hair
Loading...