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Human evolution: Forget “human hairlessness fights bugs.” Fine hairs fight bugs!

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Remember the post from yesterday that claims that it might have been the bugs that caused humans to lose their fur? Well, that item just lost shelf space to this one: In “Hairier is better – bedbugs bite our barest bits” (New Scientist Short Sharp Science, 14 December 2011), we learn that fine hairs do help deter insects:

“Men have more body hair than women, which is caused by the action of testosterone at puberty,” says Siva-Jothy. “This does not necessarily mean that women are more likely to be bitten. Blood-sucking insects are likely to have been selected to prefer to bite hosts in relatively hairless areas.”

So whatever is going on, Darwin explained it.

Question: What if comparative human hairlessness actually resulted from a genetic bottleneck in a period in which hair was not an especial asset or detriment – say, long ago on the African savannah? Thus humans emerged with little hair and chimps emerged with lots of hair (because they had already diverged from humans, and did not go through the same bottleneck.) If explanations like this turn out to have merit, we would be spared a lot of fanciful (maybe contradictory) tales about bugs and stuff.

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One Reply to “Human evolution: Forget “human hairlessness fights bugs.” Fine hairs fight bugs!

  1. 1
    Robert Byers says:

    I suggest body hair is only a later adaptation . WE were never hairy like animals.
    Our hair is from a trigger to keep us dry. Not warm.
    Thus after puberty areas of greater episodic sweating have more hair.
    Useless but its from a trigger back in the day.
    likewise men have more hair then women because we are bigger and needed to keep more dry as we had more body surface to get wet.
    Women have more hair on the head because the head loses heat more and being smaller then needed more help.

    Hair need only be seen a from biological mechanics of bodies for needs.
    People never had need of hair like animals.
    Our hair was never for warmth but for dryness which does matter for issues about warmth.
    yet our bodies over reacted to initial triggers.

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