Re: SOFT (really soft) spots

Bryce Platt (
Wed, 9 Aug 1995 12:09:42 LOCAL

In article <406ffv$> alex duncan <> writes:
>From: alex duncan <>
>Subject: SOFT (really soft) spots
>Date: 8 Aug 1995 01:43:27 GMT

>In article <405uht$> Sir CPU,

>>This is why the head of the human infant is
>>"soft" and contains a partial "soft spot" in the skull so that it is
>>better able to slip down the birth cannal.

>I'm a little baffled. If this is WHY human infants have unfused cranial
>bones (resulting in "softness"), why do the same features show up in all
>other mammals, and even birds? Do birds need a "soft" skull to get out
>of their eggs? I would think a hard skull would help them break out of
>the shell better.

>(That was sarcasm, above. I'd hate to think no one noticed.)

>There's just got to be an adaptive explanation for EVERYTHING.

>Alex Duncan
>Dept. of Anthropology
>University of Texas at Austin
>Austin, TX 78712-1086

OK, what about the obverse question?

Given that other animals have these soft spots, and that moulding of the
cranium does take place (my 4-week old granddaughter is still something of a
conehead), what explanations do we have for the smallness of the human birth
canal in relation to cranial size? My wife the obstetrics nurse says that all
the other parts can bend and twist adequately, it's just the head that is the

Not eloquently stated, but you (all) get the idea.