Re: Holloway/Morgan

Lloyd Jacobs (
29 Jul 1995 01:44:08 GMT

Elaine Morgan ( wrote:
: R. Holloway asked:

: Q. Did research into primate sweat really increase?
: A. Yes. Elizondo in 1988 reported it had "increased.within the last ten
: years".

: Q. Was that really due to AAT?
: A. No. That was probably a bit of folie de grandeur on my part

: Beginners must be baffled by obscure terms like eccrines and apocrines,
: so here is a crash course on the differences. Both are skin glands


: !. Opens into hair canal Opens onto surface of skin.

: 2.Milky exudate contains lipids. Clear saline, no lipids.

: 3. Activated at puberty. From infancy.

: 4.Exudate produced in gland Mainly an exit channel

: 5. Common in most mammals Most species have none

: 6.Serve as sweat glands in non-primates. Sweat glands in some primates

: 7. In Homo most vanish before birth. Homo has more than any other

: 8. Original purpose: pheromones. Non-slip grip on ground or branch.

: 9. Neurotransmitter: noradrenaline. Acetylcholine.

: That is the classic picture. As with many biological classifications
: the distinctions can get blurred and the functions overlap.

: In non-primates eccrines usually occur only on paws e.g.cats. In
: primates they are volar (on palms and soles) plus inside of prehensile
: tails, knuckle pads, etc. In some monkeys a sparse scattering over the
: body, apparently randomly ectopic. In the apes just over 50% of these
: skin glands are eccrine. In homo, figure in the high nineties. But the
: ape's eccrines do not function.


: This century's ace expert on primate skin, Wm. Montagna, said that
: man's unique (as he believed) eccrine sweating is so disastrously
: inefficient that it must have evolved originally for some other
: purpose. It is recklessly and pointlessly wasteful of water and salt,
: both scarce resources on the savannah. Their depletion can cause heat
: cramps, dehydration, and death. Most hot-climate mammals are
: parsimonious with their (apocrine) sweat; if their salt balance is
: threatened they may switch to sweating potassium chloride instead of
: salt.Our system behaves as if the two things in unlimited supply in
: the environment were water and salt.

: He didn't speculate on what the original purpose of eccrine sweating
: was. So I had a go. Connecting it with the similar pointlessly-profuse
: shedding of tears, I thought it might have been another reaction to
: "too much salt" (again given the unprovable premise that tears and
: sweat were once hypertonic)

: It is interesting that, as with tears, we have two kinds of eccrines,
: triggered by different stimuli. You may have noticed that your palms
: sweat freely from embarrassment or fear, but not at all from heat.

: For this theory to be plausible our ancestors must have been subject
: to a severe crisis of salinity at one time. In the AAT scenario it
: would certainly have been severe when the Sea of Afar began to
: evaporate. Some ancestral apes could have been marooned on islands
: eating sea-food from water of inexorably increasing salinity until
: some of them made it back to the mainland.

: Montagna also asked: Why has natural selection endowed the ape with
: so many eccrines when it seems to have no use for them? Well, I imagine
: the other apes evolved on the landward side of the inland sea, with
: limitless forest behind them. They wouldn't need to enter the water
: or change their traditional vegetarian diet, but when the sea
: receded the salt would have stayed in the soil and been transpired
: by the plants for a long time. When ape eccrines no longer served an
: excretory purpose they were functionless. Okay: farfetched. The cosy
: alternative explanation is..."We may never know..."

: By the way, I hope nobody still suspects the Sea of Afar of being a
: figment of AAT imagination. It is open to question whether there were
: anthropoids there, whether they were affected by the flooding and
: whether any of them survived it. But there is no question that the sea
: was there, and that it evaporated.

: I am asked: Why do no other animals show signs of having ancestors
: which underwent this ordeal?. Which ones are you thinking of? If the
: sea crashed in anything like the Med crashed through the Straits of
: Gibraltar, the original water level in flooded forest areas would be
: high. All the herbivores would drown, all the carnivores dependent on
: them would perish, the birds would fly to the mainland. The only
: mammalian survivors would be the most adaptable of the arboreal ones.

As a person with no qualifications or credentials I appreciate the info.

stuff snipped to here:

: Why the difference? Phil helpfully reminds us that the apes keep
: cool by behavioural methods: resting in the shade. It works like
: a dream. The hominids could have done the same. I will go further:
: the newly conventional mosaic scenario implies that in fact they did
: do the same. At least part time in the shady trees. Why didn't it work
: like a dream for them?

I feel that the early hominids were at times nomadic and tended to hoard
things like water. If not that, they were very good at defending water
holes. The latter may support AA theory, maybe not. I'll get to that

: AAT has a powerful reason for why there was a huge difference. By the
: time the aquatic ape returned to spending more time on land, it had
: lost the precious covering which protects the skin of most land
: mammals; it had acquired a thick insulating fat layer; it had extra
: weight to carry when it trotted around on the grass. More than enough
: reason to need to sweat, and it had to use the eccrines which had
: been unfortunately somewhat overspecialised for copious excretion.

Isn't fat good for tiding people over during famines. Since humans are
very good at surviving and adapting, they can afford the insurance
premiums of fat.

More stuff snipped

: But most of all I want to know what there was in that ancient
: savannah mosaic that is not there in the modern equivalent habitat,
: where the savannah chimpanzee effortlessly keeps its cool and says:
: "No sweat, man."

: Elaine Morgan.

I don't know about the savannah ape thing but there might be a simpler

I feel that some anthropologists might be underestimating the cleverness
of our earliest ancestors. I can't cite studies but I'm certain that
there has been research into the correlation between skull volume and
intelligence and that those studies show a rather disappointing
correlation. I would appreciate someone in this group to support or
refute this with example studies.

I also saw a stunning documentary about three people who were afflicted
with hydrocephalus at birth. Something like 70 to 85 percent of their
brain mass was destroyed (or perhaps failed to grow). Despite this the
teenagers appeared perfectly normal (behaviorally) or even bright and
doing well in school.

This led me to thinking as to why we have such big noggins if it isn't
explicitly intelligence. What I came up with is that large brains were
an effect of culture and intelligence rather than the other way round.

As we became more and more dependent on our intelligence, our brain had
to expand to make sure we had a good supply of brain cells to last ever
longer lifespans. Culture came into play and having lucid old folk
would help provide continuity in that culture. As well in case of head
injury, extra cells might come in handy in preserving the all-important

Obviously the brain cannot regenerate like other organs otherwise we
would have the brain of a newborn every 6 months or whatever. The only
way around the problem of regenerating cells was to provide a huge excess
of cells to begin with, thus providing "insurance" in case of injury or
to provide lucidity in old age.

So the bigger brained apes weren't any smarter than their neighbors but
they probably lived longer and thus could take better advantage of their
smarts and accumulate more knowledge (both individually and as a group).

Earlier on however, I see no reason why there weren't ape-like
creatures with a brain no bigger than a modern chimp but significantly
smarter. Perhaps it didn't take much. A little extra evironmental
stress here, maybe sexual selection with the intellectual ability to
recognize intelligence in potential mates there and evolution proceeds

Thus, using skull volumes to measure intelligence is stupid. :-)

What made us human was our complex (albeit small) brain right from the
beginning. Hoarding (a product of intelligence) made us bipedal. Knowing
the value of having a good constant water supply and devising plans to
defend it made us inefficient sweaters. Sexual selection, which must
have become more pronounced with intelligence could well have taken care
of body hair that we didn't need anyway because of methods to keep warm.

I do think we were just extra smart chimps and that no adaptation from
that chimp (or proto ape) physique was necessary for building a
makeshift dwelling, carrying babies and implements, or swinging a heavy
tree branch at a lion. The physical adaptations all came >>after<< we
became ever more dependent on our brain and less so on brawn.

Call it The Brainy Ape Hypothesis. (BAH) :-)


"Never underestimate the ancients." anonymous circa 2500 B.C.