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From: teexmmo@ioe.lon.ac.uk (Matthew Moore)
Newsgroups: sci.skeptic,sci.bio
Subject: Re: Further Evolving Eyebrows
Message-ID: <1990Nov5.123912.15186@ioe.lon.ac.uk>
Date: 5 Nov 90 12:39:12 GMT
References: <1371@cluster.cs.su.oz.au> <2431@anaxagoras.ils.nwu.edu>
Reply-To: teexmmo@ioe.lon.ac.uk (Matthew Moore)
Organization: Institute of Education University of London
Lines: 25

Jorn Barger > writes:
>
>I've been waiting for years for someone to ask me this (why do humans have 
>eyebrows).  It seems transparently obvious to me that they are primarily 
>_signal-flags_, bars of contrasting color that amplify our emotional 
>expressions, making them readable more easily at a greater distance.
>
>Why did humans lose their fur?  This seems surely due to sexual selection, 
>not natural selection.  But why this baldness became sexually attractive I 
>have no clue. 
>

It may be "transparently obvious" to you, but this does not make it
the only explanation in the literature.

The Hardy-Morgan theory of human evolution (aka the aquatic theory)
considers eyebrows to be sunshades. What do you do if the sun gets in
your eyes? - You frown, or lower your eyebrows.

Loss of fur is a common adaptation to aquatic life (or semi aquatic
life), consider the elephant, pig, hippoo, cetaceans (whales and dolphins).
Indeed, Hardy first formed his theory when, on his return from a
whaling trip, he was struck by the similarity between whale blubber
and the human layer of subcutaneous fat.
(Subcutaeneous fat being an aquatic adaptation against heat loss).