Re: Why is Homo sapiens hairless?

John Waters (
29 Oct 1996 22:29:04 GMT

Rohinton Collins <> wrote in
article <01bbc532$51691b20$LocalHost@dan-pc>...

> And why isn't the manufacture of clothes simple? If Homo
> used stone tools to butcher carcasses which (s)he may
have scavenged or
> hunted and likely brought back to his/her home base, then
why could (s)he
> not have fashioned simple garments out of the dried skins
left over.
> Indeed, for an animal capable of making stone tools it
would be less
> believable to suggest that (s)he would be unable to
tailor simple garments.
> The AAT seems an overly complicated theory to me which is
supported by
> little evidence, or logical thought.

Skins are distinctly biodegradable. They need processing
they can become useful garments. Skins have to be tanned
they become durable leather. In addition, they have to be
scraped, stretched
and chewed to be made supple. You need needles and thread
to join them. Cat gut has to be manufactured. It is not an
business. Even making clothes than fit well is difficult.
It requires knowledge and a lot of technology.

I agree with you that AAT is not very logical or well
thought out.
But is your idea any more logical? As other posts have
are you not putting the cart before the horse?

Consider the Helpless Baby Theory. It really is simple,
arguably logical). Human babies are helpless for a much
time after birth than ape babies. Fact. When the hominid
started to become helpless for longer periods after birth,
mothers had to carry them in their arms. (As now.) Fact.

When a baby is carried in its mothers arms, there is a
change in
its effective surface to mass ratio. Fact. This is because
percent of the baby€s skin is in direct contact with the
This causes the baby€s core body temperature to rise. If
core temperature continues to rise the baby could die of
heat-stroke. Fact.

This creates evolutionary pressure to reduce the dangers of
infantile overheating. This leads to the moulting of the
fetal hair
in hominid infants. Fact. It also leads to the development
subcutaneous fat in the female, where the fat is
concentrated in
the areas of the female body which come into direct contact
the infant, when it is carried by its mother. Fact.

The mother€s subcutaneous fat insulates the baby from the
mother€s own internal body heat. Fact.

The subcutaneous fat of the female leads to evolutionary
pressure for less body hair in the female. This is the
situation. Fact.

In Chimpanzee and Gorilla species, the juveniles stay with
mother and share her nest until adolescence. After
maturity, the
young males are driven out by the alpha male. Fact.

If this pattern of behaviour was also true of hominids, the
males would need body hair after puberty. And this is what
happens. Fact.

Simple, parsimonious, logical and reasonable. The only real
problem with the Helpless Baby Theory is that it is based
upon the facts.


John Waters is the author of "Helpless as a Baby",
a book concerned with general and human
evolution. It may be accessed at URL