Re: Is the AAH a legitimate hypothesis? Of course it is.

From: Pauline M Ross (pmross_at_ross-software.co.uk)
Date: 02/01/05 

Date: Tue, 01 Feb 2005 16:05:28 +0000

On Tue, 01 Feb 2005 01:39:47 GMT, "Bob Keeter" <rkeeter@earthlink.net>
wrote:

>> Infant fat may or may not be related to aquaticism. It may or may not
>> be related to the energy requirements of the large human brain.
>
>With you 100%! Since we DON'T know, could you please tell
>the "hard core", that "don't know"'s cant be used as proofs? 8-)

I don't think the "hard core" (do you mean Algis and Marc ?!?) use
infant fat as proof of anything. It is a piece of evidence, that is
all.

>> Yes, but... harp seals need to be born fat because their food supply
>> is withdrawn soon after birth; guinea pigs need to be born fat because
>> their mother's milk is nutritionally poor. Neither of these situations
>> applies to human infants. A primate mother is always around to feed
>> her infant on demand, and human milk supplies all the infant needs. So
>> what is the fat for? It isn't even used, in normal circumstances, only
>> in a crisis (and only a short-term crisis, at that). So you are left
>> with a 'just-in-case' provision. I don't know about you, but I don't
>> find that particularly convincing.
>
>Ah, but is not the sufficiency of the food source sort of tied in to the
>underlying needs of the consumer? Ungulants lead a relatively
>placid life and get by on pretty sorry fodder (at least in terms of
>caloric, protein, and fat content). High activity animals, ranging from
>predators to humming birds need higher quality more "nutrient rich"
>food sources. A human baby needs to "feed" a rapidly growning
>brain that certainly the guinea pig does not have to worry about.
>On the other hand, in one case the requirement is in comparison great,
>in the other the supply is defient. Could the same adaptation be
>answering both needs?

Well, supply and demand are two sides of the same coin. The fact is
that for a healthy human infant, all its energy needs for maintenance
and growth are normally met by its mother's milk (since the fat isn't
normally used up until around 4 years of age).

All the signs (such as relatively dilute milk and difficulty in
re-establishing lactation after it has stopped) suggest that humans
follow the standard primate pattern of infant staying close to mum,
feeding on demand, getting good quality milk and without significant
interruptions. This is quite different from the harp seals and guinea
pigs. With humans, it really is quite difficult to see why so much fat
is needed. 

-- 
Pauline Ross

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