Re: Breastfeeding and Noses.
John Waters (jdwaters@dircon.co.uk)
30 Aug 1996 00:30:30 GMT
My thanks to Barry and Andrew. It is very kind of them to offer their
expert opinions on this matter. Despite Barrys apparent vote of
confidence, I must admit I remain a little uneasy about my proposal.
I can well appreciate the need for the reflex action described by
Andrew. If the infants nose was blocked by mucus, or by blood from
a nosebleed, such a reflex would be a vital survival mechanism.
In addition, the proposal that the change in hominid nose physiology
was due to breathing/feeding problems seems a little too obvious. In
this regard, I have often found in the course of my evolution
research that OBVIOUS answers are invariably WRONG answers.
Nevertheless, when the proposal is put in to its evolutionary context
Andrew may perceive the source of my dilemma. In particular, I
would draw Andrews attention to the change in hominid skull
morphology which occurred within the last million years. It is evident
that there was a steady reduction in the Ape-like muzzle. This was
presumably matched by a consequential reduction in the nipple of
the nursing female.
In this context, prior to each consequential reduction in nipple length,
the infant would tend to choke on the relatively long nipple, and this
would create the evolutionary pressure for a reduction in nipple
length. As far as the nose is concerned, this evolutionary feedback
loop would have no immediate effect on nose physiology. The nose
would remain in its Gorilla/Chimpanzee state, with forward facing
nostrils.
However, when changes in hominid skull morphology reduced the
hominid muzzle to its present day proportions, the forward facing
nostrils would come into direct contact with the nursing females
breast during suckling. This, coupled with the short muzzle/long
nipple problem, would put the infant into double jeopardy.
My dilemma is this. I can demonstrate the evolution of the relatively
large Jewish/Arab nose by another evolutionary mechanism.
However, I cannot bridge the gap between the ape-like forward
facing nostrils, and the present day Asian/African, short nose
physiology. My proposal could be correct, but it seems too obvious.
Do you think the change could be due to olfactory rather than
respiratory evolutionary pressure?
John Waters
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