Bipedialism and other factors and AAT
Sir CPU
locomotion in comparison to other animals. Much has been claimed
in this news group that humans have an efficient means of
locomotion. That might be somewhat true for walking, but it is NOT
true for running, especially in comparison to other animals. I think
this would present some problems on an open African savanna environment.
Much of this information is taken from The Cambridge Encyclopedia of
Human Evolution, Cambridge University Press, copyright 1992
There is apparently no clear difference in the efficiency of locomotion
of bipeds in comparison to quadrupeds, this is according to R. McNeill
Alexander. This is something I did not realize. And as a GENERAL
statement it is true. But only because it includes such efficient
bipeds as ostriches and kangaroos, of which the later uses a totally
different means of locomotion than humans do.
This "efficiency rating" based on the formula P = P(o) + C(v)
Where P = power
P(o) = power used when stationary
V = Speed
C = Energy used in traveling a unit distance, over and above
what would be used if standing still
This formula reveals that "some species are unusually economical for
their size, whereas other are unusually extravagant of energy. For
example, a penguin which waddles in an ungainly way, uses
proportionately twice as much energy for traveling overland as a
graceful gazelle."
And guess where humans fall??
Slightly better than the penguin, but not quite as good as a pony,
which apparently is a rather inefficient quadruped for it's size. The a
formula also shows that "running is a little more costly for us than
for typical mammals of equal body weight. Human walking is less
costly."
Those grouped into the efficient column, using this formula would be
the quail, the dog, the gazelle, and the ostrich. Those in the
inefficient
group would be the goose, the penguin, the human, and the pony.
So as long as we did not have to run from any predators, we were OK.
According to R. McNeill Alexander, "Not only are we rather
uneconomical runners, we are also rather slow"
Combine this with the problem of sweating, and you have an animal
that is slow, and inefficient at moving with any significant degree of
speed, and needs to be near water to replenish lost fluids.
The fact is that "Active young men will normally lose over 8 litres of
water during a day when the desert temperature at midday is above
40 C." "A man weighing 90 kilograms can sweat over 2 liters of water
in an hour of normal walking in a hot day in the desert."
It would seem to me that since we were, and still are not a
particularly fast or agile creature; combined with our tendency to
suffer from a high degree of dehydration that occurs in moderately
hot climates; combined with an unusually hairless body; combined
with eyes that make it possible to only become active during the
light of day and not the coolness of night; combined with not
especially good hearing when compared with other creatures who
can hear over the vast distances of the great plains; would lead one
to the conclusion that we must have evolved in a safe, shady, semi-
aquatic environment.
Troy Kelley
John D. Brennan IV
sir...@aol.com (Sir CPU) writes:
> According to R. McNeill Alexander, "Not only are we rather
> uneconomical runners, we are also rather slow"
Troy,
Perhaps I'm mistaken, but I believe that the same arguement was used
as evidence that chimps were just a leftover of the evolution of man.
Later they found out that a chimp was highly efficient and evolved for
walking along a branch/line not the ground, just like another
"inefficient" species, squirrels (who are slow "bouncy" runners but
greased lightening in a tree). The point is, man evolved to walk, not
run, it's what we do best, just like the other "inefficient" species
you mentioned, penguins, who are extremely efficient in the water. So
to recap, man's mode of transportation is walking, just like chimps and
squirrels climb and walk branches, and the penguins swim, running is an
extra and hence inefficient for all of the above.
--John (just an old Bio/Anthro major, fire at will! (smile))
HARRY R. ERWIN
of a six-year-old (with at best comparable mobility), but the comparison
should be with quadrupeds of the same leg-length and approximate mass, not
with modern man. Efficiency and range will be comparable then. The
interesting point is that a biped has two advantages over the quadruped:
the head is about twice as far off the ground, and the hands and arms do
not need to be modified for terrestrial support. Based on mechanical
factors, Lucy and OH-62 had comparable forearm climbing abilities to
orangs and were superior to gorillas and chimps. (The fingers and palms of
knuckle-walkers are modified for compressive strength. This reduces their
efficiency at grasping tree limbs.)
--
Harry Erwin
Internet: her...@gmu.edu
PhD student in comp neurosci: "Glitches happen" & "Meaning is emotional"
Sir CPU
-run, it's what we do best, just like the other "inefficient" species
-you mentioned, penguins, who are extremely efficient in the water. So
-to recap, man's mode of transportation is walking, just like chimps and
-squirrels climb and walk branches, and the penguins swim, running is an
-extra and hence inefficient for all of the above.
-John (just an old Bio/Anthro major, fire at will! (smile))
The point I was trying to make though is that man's inefficiency of
running is not helpful when being pursued by a predator. And it seems to
me that this would happen often if man evolved for any lenght of time on
the open savannas. It wouldn't matter how efficient walking was, running
it what really counts when a lion is chasing you.
The points you make about other species isn't a good comparison
because all of them are fast at least SOMEWHERE and primarily where they
are most likely to be prusued by predators. Penguins may not be able to
walk efficiently, but the majority of their predators are in the water
(Killer Whales and Leapord Seals). Consequently they manage to out race
their attackers in the water. They are lucky they have no major predators
on land. Perhaps this is why they choose to raise there young out in the
open on land.
Squirrels might not be efficient on the ground, but they are never
far from a tree, and at the first sign of trouble, they make a dash for a
tree. They are obviously vulnerable on the land, and this is where a
predator is most likely to catch a squirrel.
Troy Kelley
Brad Woodcock
*Excessive eradication of post here*
>It would seem to me that since we were, and still are not a
>particularly fast or agile creature; combined with our tendency to
>suffer from a high degree of dehydration that occurs in moderately
>hot climates; combined with an unusually hairless body; combined
>with eyes that make it possible to only become active during the
>light of day and not the coolness of night; combined with not
>especially good hearing when compared with other creatures who
>can hear over the vast distances of the great plains; would lead one
>to the conclusion that we must have evolved in a safe, shady, semi-
>aquatic environment.
>Troy Kelley
This isn't a direct response to this particular post, but it is the thing
that brought this to mind again. Where in the world did this idea come from
that Australos dropped out of the trees and immediately began living
strictly on the savannah far from trees? They were obviously partially
arboreal, and they were tiny! A 40kg creature without any real natural
weaponry isn't much of a threat, overall. Doesn't it make more sense that
Australos lived in the borderlands between savannah and deep forest?
Possibly sleeping in or near trees for safety (as some baboons do), foraging
the borderland, and taking short forays for food farther into the forest,
and also out onto the more flat, less wooded savannah. This demonstrates a
larger variety of food resources, without requiring a huge increase in
foraging distances. I'm not sure what would cause them to move out into the
borderlands though. It could be that the forest was becoming smaller and
they were out competed by something in the forest (like monkeys). I could
just be that they were competed out of the forest by something (once again,
probably monkeys) but didn't quite have what it took to live on the
savannah. Something I've been very curious about, and which I have seen
mostly sidestepped or ignored completely is the question of what kinds of
animals would the A. Afarensis been competing against? What size predators,
and scavengers were around on the savannah, lightly wooded, and forest areas
of eastern Africa 3-2.5mya? This could be very important. If we're talking
about 10 40kg males and 12 30kg females taking on something along the lines
of a giant hyena or a lion something like twice the size of the ones around
today, I think the only recourse they could possibly have is heading into
the trees for safety. Finger nails, small canines and small body weight are
not the weapons I would ask for if I had to try to defend myself from
something that big and nasty. Even if we assume that the intelligence of
the Australopiths was significantly helpful in these situations, and that
they had weapons of some sort, that still makes for a very one sided fight.
--
Brad Woodcock The Trolls Guild
wood...@horus.cecer.army.mil "We're here to make you
brad-...@nova.novanet.org appreciate normal people."
Work:(217)352-6511 x7590 Home:(217)344-0363
HARRY R. ERWIN
: -The point is, man evolved to walk, not
: -run,... (trimmed)
: The point I was trying to make though is that man's inefficiency of
: running is not helpful when being pursued by a predator. And it seems to
: me that this would happen often if man evolved for any lenght of time on
: the open savannas. It wouldn't matter how efficient walking was, running
: it what really counts when a lion is chasing you.
Actually it doesn't matter much by that point. Your likely to be better of
standing your ground (with a few others). What matters is spotting the
lion at a distance. There bipedalism is superior.
: The points you make about other species isn't a good comparison
: because all of them are fast at least SOMEWHERE and primarily where they
: are most likely to be prusued by predators. Penguins may not be able to
: walk efficiently, but the majority of their predators are in the water
: (Killer Whales and Leapord Seals). Consequently they manage to out race
: their attackers in the water. They are lucky they have no major predators
: on land. Perhaps this is why they choose to raise there young out in the
: open on land.
Based on the skeletal features, A. was one hell of a fast tree climber
(equal to Pongo in this regard).
: Squirrels might not be efficient on the ground, but they are never
: far from a tree, and at the first sign of trouble, they make a dash for a
: tree. They are obviously vulnerable on the land, and this is where a
: predator is most likely to catch a squirrel.
: Troy Kelley
--
J. Moore
And, as you've read in my other post(s), we almost certainly did not
have to depend on running for defense from predators. Certainly not
any long distance. So we were, as you state above, okay. But to
realise this, you have to look at what we and our close relatives
actually do, rather than what you would imagine they should do.
Si> Combine this with the problem of sweating, and you have an animal
Si> that is slow, and inefficient at moving with any significant degree of
Si> speed, and needs to be near water to replenish lost fluids.
Si> The fact is that "Active young men will normally lose over 8 litres of
Si> water during a day when the desert temperature at midday is above
Si> 40 C." "A man weighing 90 kilograms can sweat over 2 liters of water
Si> in an hour of normal walking in a hot day in the desert."
First of all, who the hell ever said that australopithecines *ever* set
foot in the desert (besides you)?
Second, look at Peter Wheeler's (1994) statement:
"The estimated total daytime drinking water requirements of a 35 Kg
naked biped, utilising heat storage and foraging throughout the day at
the temperatures and level of metabolic expenditure used in the present
study [note: 35-40 degree C temperatures and a 12 hour foraging day,
rather longer than likely actually], is approximately 1.3 litres, the
equivalent of 3.7% of its total body mass. Since this degree of
dehydration can be tolerated by modern humans without experiencing any
major detrimental effects, this indicates that these animals should not
usually have required access to drinking water more than once a day
(Wheeler, 1991b). If the normal activity pattern of these primates also
involved shade-seeking during the most thermally stressing period of the
day, their requirements will have been substantially lower. Intakes as
low as 0.7 litre, equivalent to only about 2% of total body mass, may
have been sufficient to replace all losses incurred by a naked biped
throughout the day if it retreated into the shade for a 4-hour period in
the early afternoon [note: this is the common mode of activity in hot
climates for humans, chimps, gorillas, and indeed a whole lot of
animals; "mad dogs and Englishmen" and all that]."
Si> can hear over the vast distances of the great plains; would lead one
Si> to the conclusion that we must have evolved in a safe, shady, semi-
Si> aquatic environment.
Si> Troy Kelley
"Shady" at the seashore? You've *never* been to the beach? Safe? From
crocs and sharks we can't even see approaching? And which don't respond
to human and chimpanzee threat displays (as big cats and other land
predators do)?
Jim Moore (j#d#.mo...@canrem.com)
Refs:
Wheeler, Peter
1991b [I don't have the title here at present, sorry]. *Journal of
Human Evolution* 21:117-136
Wheeler, Peter
1994 "The thermoregulatory advantages of heat storage and shade-seeking
behavior to hominids foraging in equatorial savannah environments".
*Journal of Human Evolution* 24(4):339-350, April.
* Q-Blue 1.0 *
Troy Kelley
From: J. Moore, j#d#.mo...@canrem.com
Date: Sat, 3 Jun 95 12:40:00 -0500
In article <60.1658.72...@canrem.com> J. Moore,
j#d#.mo...@canrem.com writes:
>Si> So as long as we did not have to run from any predators, we were OK.
>
>And, as you've read in my other post(s), we almost certainly did not
>have to depend on running for defense from predators. Certainly not
>any long distance. So we were, as you state above, okay. But to
>realise this, you have to look at what we and our close relatives
>actually do, rather than what you would imagine they should do.
If you are talking, in some sort of round about way, about threat
displays, I realize of course that SOME animals exhibit threat displays
when cornered by a predator. By "our close relatives" I assume you mean
chimps and gorrillas, but they are not currently under a lot of predation
except from man. So they exhibit very little predatoral threat displays.
I think you are mainly talking about baboons which exhibit threat
displays as part of a defense, but this is also because they are
primarily savanna creatures which do not have the luxury of running to a
tree every time danger is encountered.
>Si> Combine this with the problem of sweating, and you have an animal
>Si> that is slow, and inefficient at moving with any significant degree
of
>Si> speed, and needs to be near water to replenish lost fluids.
>
>Si> The fact is that "Active young men will normally lose over 8 litres
of
>Si> water during a day when the desert temperature at midday is above
>Si> 40 C." "A man weighing 90 kilograms can sweat over 2 liters of water
>Si> in an hour of normal walking in a hot day in the desert."
>
>First of all, who the hell ever said that australopithecines *ever* set
>foot in the desert (besides you)?
Gee.. I didn't realize I said "Australopithecines set foot in the
desert". Thank you for explaining to me what I said.
I was mearly using a quote I had found about water consumption to
illustrate a point that hominids, when compared to other savanna
creatures, do not conserve water very well.
>
>Second, look at Peter Wheeler's (1994) statement:
>
>"The estimated total daytime drinking water requirements of a 35 Kg
>naked biped, utilising heat storage and foraging throughout the day at
>the temperatures and level of metabolic expenditure used in the present
>study [note: 35-40 degree C temperatures and a 12 hour foraging day,
>rather longer than likely actually], is approximately 1.3 litres, the
>equivalent of 3.7% of its total body mass. Since this degree of
>dehydration can be tolerated by modern humans without experiencing any
>major detrimental effects, this indicates that these animals should not
>usually have required access to drinking water more than once a day
>(Wheeler, 1991b). If the normal activity pattern of these primates also
>involved shade-seeking during the most thermally stressing period of the
>day, their requirements will have been substantially lower. Intakes as
>low as 0.7 litre, equivalent to only about 2% of total body mass, may
>have been sufficient to replace all losses incurred by a naked biped
>throughout the day if it retreated into the shade for a 4-hour period in
>the early afternoon [note: this is the common mode of activity in hot
>climates for humans, chimps, gorillas, and indeed a whole lot of
>animals; "mad dogs and Englishmen" and all that]."
You can use all the quotes on water consumption you want and I promise
you I can find quotes that will contradict you. I did however noticed
that the first part of this reference was an "estimate". I think that
the "estimated total daytime drinking requirements" by this author was a
very poor estimate.
I don't think there is really any question, no matter what quote you come
up with, that the susceptibility of early hominids to dehydration was
probably pretty high. If you look at any other creature on the savanna,
the ways in which they conserve water resources are far superior to the
human/pre-human model. Their body temperatures are generally higher,
they allow their internal body temperatures to rise in response to heat
and they don't sweat, they pant. Sweating may be an efficient cooling
mechanism for humans, but it is not an effective way to stay cool unless
there is access to plenty of water to re-hydrate the body. I really
don't think there is any argument about this.
>
>Si> can hear over the vast distances of the great plains; would lead one
>Si> to the conclusion that we must have evolved in a safe, shady, semi-
>Si> aquatic environment.
>Si> Troy Kelley
>
>"Shady" at the seashore? You've *never* been to the beach? Safe? From
>crocs and sharks we can't even see approaching? And which don't respond
>to human and chimpanzee threat displays (as big cats and other land
>predators do)?
>J. Moore, j#d#.mo...@canrem.com
"You've *never* been to the beach?" - Now theres a good, well thought
out, non-antagonistic question.
And to use one of your previous quotes - "Who the hell said anything
about a seashore?" I don't think DRINKING sea water for re-hydration
would be a very effective way to say alive on the Africa savanna.
And besides that, I don't think crocodiles like salt water, in fact, I
know that they don't live in salt water.
Haven't you ever been to the beach?
Troy Kelley
Drew Talley
[lots deleted]
: And besides that, I don't think crocodiles like salt water, in fact, I
: know that they don't live in salt water.
C. porosus lives almost entirely in the ocean, often swimming several
miles out to sea. Many other species show varying tolerances for
salinity.
Drew
tal...@sunstroke.sdsu.edu
or
dta...@ucsd.edu
: Troy Kelley
J. Moore
Tk> Subject: Re: Bipedialism and other factors and AAT
Tk> X-Xxdate: Tue, 6 Jun 95 13:49:41 GMT
Tk> Subject: Re: Bipedalism and other factors and AAT
Tk> From: J. Moore, j#d#.mo...@canrem.com
Tk> Date: Sat, 3 Jun 95 12:40:00 -0500
Just as a matter of curiousity, why do you continually use the incorrect
spelling of bipedalism ("bipedialism") in your subject lines, even to
the point of changing it back after I've corrected it?
Tk> If you are talking, in some sort of round about way, about threat
Tk> displays, I realize of course that SOME animals exhibit threat displays
Tk> when cornered by a predator. By "our close relatives" I assume you mean
Tk> chimps and gorrillas, but they are not currently under a lot of
Tk> predation except from man. So they exhibit very little predatoral
Tk> threat displays. I think you are mainly talking about baboons which
Tk> exhibit threat displays as part of a defense, but this is also because
Tk> they are primarily savanna creatures which do not have the luxury of
Tk> running to a tree every time danger is encountered.
You are, of course, incorrect. In the post(s) I referred to, I talked
about chimpanzees, not baboons, and the way they react to predators.
You are again incorrect when you state that chimpanzees are not under
pressure from non-human predators.
Tk> The fact is that "Active young men will normally lose over 8 litres
Tk> of
Tk> water during a day when the desert temperature at midday is above
Tk> 40 C." "A man weighing 90 kilograms can sweat over 2 liters of
Tk> water
Tk> in an hour of normal walking in a hot day in the desert."
Tk> >
JM> >First of all, who the hell ever said that australopithecines *ever* set
JM> >foot in the desert (besides you)?
Tk> Gee.. I didn't realize I said "Australopithecines set foot in the
Tk> desert". Thank you for explaining to me what I said.
Tk> I was mearly using a quote I had found about water consumption to
Tk> illustrate a point that hominids, when compared to other savanna
Tk> creatures, do not conserve water very well.
You gave a quote about how much water can be lost by active humans in
the desert, which has nothing whatsoever to do with australopithecines
unless they were in the desert. So your quote has nothing whatsoever to
do with the subject at hand. (Question: How much water would, say, a
wildebeest use in "an hour of walking in a hot day in the desert"?
Answer: who cares? the desert has nothing to do with its actual habitat.)
Tk> You can use all the quotes on water consumption you want and I promise
Tk> you I can find quotes that will contradict you.
Please do. Please also make sure that these quotes have something to do
with the actual habitat and level of activity that is relevant for
austrolopithecines. That would be a hot, wooded savannah mosaic
environment and creatures that act as chimps, gorillas, and indeed
virtually all animals do in that environment: moving about sporadically
rather than steadily, and resting in the readily available shade during
the hottest parts of the day. I'm afraid this leaves out quotes about
marathon running and walking through the desert.
Tk> I did however noticed
Tk> that the first part of this reference was an "estimate". I think that
Tk> the "estimated total daytime drinking requirements" by this author was a
Tk> very poor estimate.
Peter Wheeler's articles are readily available, and his research
techniques are stated in them. Feel free to counter his research with a
critique of his methods. Otherwise, "I think that [this] was a very
poor estimate" is simply a statement without basis, from someone who not
only hasn't read the work, but who doesn't seem to understand how
walking in the desert differs from foraging and resting in a wooded
savannah mosaic environment.
Here, to help you in your critique, are the years, volume numbers, and
page numbers for Peter Wheeler's articles in *Journal of Human
Evolution*: 1984, vol 13:91-98; 1985, vol 14:23-28; 1990, vol
19:321-322; 1991, vol 21:107-115; 1991, vol 21:117-136; 1992 vol
23:379-388; 1992, vol 23:351-362; 1993, vol 24:13-28; 1994, vol
26:339-350.
Tk> I don't think there is really any question, no matter what quote you
Tk> come up with, that the susceptibility of early hominids to dehydration
Tk> was probably pretty high. If you look at any other creature on the
Tk> savanna, the ways in which they conserve water resources are far
Tk> superior to the human/pre-human model. Their body temperatures are
Tk> generally higher, they allow their internal body temperatures to rise in
Tk> response to heat and they don't sweat, they pant. Sweating may be an
Tk> efficient cooling mechanism for humans, but it is not an effective way
Tk> to stay cool unless there is access to plenty of water to re-hydrate the
Tk> body. I really don't think there is any argument about this.
And yet they *were* there; oh, not in the treeless and waterless
savannah that you imagine, but in the actual savannah environment that
existed in reality. And they were there for millions and millions of
years, which fact even the AAH accepts. So it is obvious that they
could and in fact did live and indeed thrive there.
Tk> >Si> to the conclusion that we must have evolved in a safe, shady, semi-
Tk> >Si> aquatic environment.
Tk> >Si> Troy Kelley
Tk> >
Tk> "Shady" at the seashore? You've *never* been to the beach?
Tk> "You've *never* been to the beach?" - Now theres a good, well thought
Tk> out, non-antagonistic question.
Tk> And to use one of your previous quotes - "Who the hell said anything
Tk> about a seashore?"
Hardy and Morgan, the principle architects of the AAH.
Tk> I don't think DRINKING sea water for re-hydration
Tk> would be a very effective way to say alive on the Africa savanna.
I would agree, but of course, there is no need to go around drinking sea
water in a wooded savannah environment, as opposed to the putatively
aquatic ancestor.
JM> Safe? From
JM> crocs and sharks we can't even see approaching? And which don't
JM> respond
JM> to human and chimpanzee threat displays (as big cats and other land
JM> predators do)?
Tk> And besides that, I don't think crocodiles like salt water, in fact, I
Tk> know that they don't live in salt water.
"It's not what he doesn't know that scares me, but all the things he
knows for sure that just ain't so." You invite scathingly critical
replies when you post nonsense when you could easily check your facts
first. The estuarian crocodile, as has already been pointed out to you,
inhabits salt-water (that's why it's often called the "salt-water
crocodile") and is the largest, and some say the most vicious, of the
crocodiles. Since not only is this information easy to find in any
library, but has in fact been posted in the AAH threads here and
elsewhere several times, one is lead to the feeling that you are not
merely ignorant of many things you profess to know, but in fact are
*willfully* ignorant. You *could* change that, you know.
Tk> Haven't you ever been to the beach?
Tk> Troy Kelley
Yes, I have, but didn't swim or wade, due to the prevalence of shark
attacks in the area.
Jim Moore (j#d#.mo...@canrem.com)
* Q-Blue 1.0 *
Troy Kelley
Date: Sat, 10 Jun 95 14:36:00 -0500
In article <60.1715.72...@canrem.com> J. Moore,
j#d#.mo...@canrem.com
writes:
>Tk> If you are talking, in some sort of round about way, about threat
>Tk> displays, I realize of course that SOME animals exhibit threat
displays
>Tk> when cornered by a predator. By "our close relatives" I assume you
mean
>Tk> chimps and gorrillas, but they are not currently under a lot of
>Tk> predation except from man. So they exhibit very little predatoral
>Tk> threat displays. I think you are mainly talking about baboons which
>Tk> exhibit threat displays as part of a defense, but this is also
because
>Tk> they are primarily savanna creatures which do not have the luxury of
>Tk> running to a tree every time danger is encountered.
>
>You are, of course, incorrect. In the post(s) I referred to, I talked
>about chimpanzees, not baboons, and the way they react to predators.
>You are again incorrect when you state that chimpanzees are not under
>pressure from non-human predators.
The fact is, chimpazees have very few natural (non-human) predators in
the wild
and will live to a ripe old age in the wild.
>
>Tk> The fact is that "Active young men will normally lose over 8 litres
>Tk> of
>Tk> water during a day when the desert temperature at midday is above
>Tk> 40 C." "A man weighing 90 kilograms can sweat over 2 liters of
>Tk> water
>Tk> in an hour of normal walking in a hot day in the desert."
>Tk> >
>JM> >First of all, who the hell ever said that australopithecines *ever*
set
>JM> >foot in the desert (besides you)?
>
>Tk> Gee.. I didn't realize I said "Australopithecines set foot in the
>Tk> desert". Thank you for explaining to me what I said.
>
>Tk> I was mearly using a quote I had found about water consumption to
>Tk> illustrate a point that hominids, when compared to other savanna
>Tk> creatures, do not conserve water very well.
>
>You gave a quote about how much water can be lost by active humans in
>the desert, which has nothing whatsoever to do with australopithecines
>unless they were in the desert. So your quote has nothing whatsoever to
>do with the subject at hand. (Question: How much water would, say, a
>wildebeest use in "an hour of walking in a hot day in the desert"?
>Answer: who cares? the desert has nothing to do with its actual habitat.)
The point was still that hominids do not conserve water very well, IN
ANY KIND OF HABITAT. I understand that they do not live in the desert
but I was merely pointing to their unusually high water consumption rates.
Did I not make that clear?
>
>Tk> You can use all the quotes on water consumption you want and I
promise
>Tk> you I can find quotes that will contradict you.
>
>Please do. Please also make sure that these quotes have something to do
>with the actual habitat and level of activity that is relevant for
>austrolopithecines. That would be a hot, wooded savannah mosaic
>environment and creatures that act as chimps, gorillas, and indeed
>virtually all animals do in that environment: moving about sporadically
>rather than steadily, and resting in the readily available shade during
>the hottest parts of the day. I'm afraid this leaves out quotes about
>marathon running and walking through the desert.
>
>Tk> I did however noticed
>Tk> that the first part of this reference was an "estimate". I think
that
>Tk> the "estimated total daytime drinking requirements" by this author
was a
>Tk> very poor estimate.
>
>Peter Wheeler's articles are readily available, and his research
>techniques are stated in them. Feel free to counter his research with a
>critique of his methods. Otherwise, "I think that [this] was a very
>poor estimate" is simply a statement without basis, from someone who not
>only hasn't read the work, but who doesn't seem to understand how
>walking in the desert differs from foraging and resting in a wooded
>savannah mosaic environment.
If you really think I don't understand "how walking in the desert
differs from foraging and resting in a wooded savannah mosaic environment"
then I don't think you understood the point I was trying to make at all.
Yes, they thrived in an environment that had the necessary aquatic
resources in order to replenish any fluids lost during the hot day.
I think you are still missing the point here. The AAH argument is that if
hominids
evolved EXCLUSIVELY in a savanna environment, then why don't they
conserve water
resources as well as other savanna creatures?
>
>Tk> >Si> to the conclusion that we must have evolved in a safe, shady,
semi-
>Tk> >Si> aquatic environment.
>Tk> >Si> Troy Kelley
>Tk> >
>Tk> "Shady" at the seashore? You've *never* been to the beach?
>
>Tk> "You've *never* been to the beach?" - Now theres a good, well thought
>Tk> out, non-antagonistic question.
>
>Tk> And to use one of your previous quotes - "Who the hell said anything
>Tk> about a seashore?"
>
>Hardy and Morgan, the principle architects of the AAH.
Yes, but I never said anything about the sea shore. Personnally, I think
most
of the aquatic phases took place in fresh water rivers, lakes and
streams. It
is possible that some swimming, diving, foraging did occur in the ocean,
but this
is not good drinking water, so there must have been fresh water nearby.
>Tk> I don't think DRINKING sea water for re-hydration
>Tk> would be a very effective way to say alive on the Africa savanna.
>
>I would agree, but of course, there is no need to go around drinking sea
>water in a wooded savannah environment, as opposed to the putatively
>aquatic ancestor.
>
>JM> Safe? From
>JM> crocs and sharks we can't even see approaching? And which don't
>JM> respond
>JM> to human and chimpanzee threat displays (as big cats and other land
>JM> predators do)?
>
>Tk> And besides that, I don't think crocodiles like salt water, in fact,
I
>Tk> know that they don't live in salt water.
>
>"It's not what he doesn't know that scares me, but all the things he
>knows for sure that just ain't so." You invite scathingly critical
>replies when you post nonsense when you could easily check your facts
>first. The estuarian crocodile, as has already been pointed out to you,
>inhabits salt-water (that's why it's often called the "salt-water
>crocodile") and is the largest, and some say the most vicious, of the
>crocodiles. Since not only is this information easy to find in any
>library, but has in fact been posted in the AAH threads here and
>elsewhere several times, one is lead to the feeling that you are not
>merely ignorant of many things you profess to know, but in fact are
>*willfully* ignorant. You *could* change that, you know.
The estuarian crocodile lives in ESTUARIES which are BRACKISH; or
mixtures of some
salt with but mostly fresh water. If these crocodiles are exposed to the
kinds of
salt levels found in the ocean for a long enough period of time, they
will die.
Besides, crocodiles living in salt water, even though you seem to latch
on to this
issue rather quickly, is not the real issue for this news group. I was
not
implying that an aquatic environment was free from predators. I was
merely
pointing out that given our many physical deficiencies, which I am not
going to
list again, we must have evolved in a relatively safe environment. We
may have
developed defensive strategies to help avoid crocodiles. And I have
stated in this
news group before, that I would imagine it would be easier to deal with
crocodiles
as a predator than it would be to deal with lions, or big cats on the
open plains.
The first reason is because crocodiles lay their eggs in shallow nests
around the
edges of their aquatic environment and do very little to defend these
nests.
These eggs would make a very good meal for early hominids and it would be
an
effective way to control the population of crocodiles as a whole. I
doubt if
early hominids would have any chance of making a meal out of lion cubs or
leopard
kittens. Secondly, crocodiles are dumb. They are much dumber than
lions, and I
would imagine that a defensive strategy could be developed to deal with
them after
some examination of their habits.
>
>Tk> Haven't you ever been to the beach?
>Tk> Troy Kelley
>
>Yes, I have, but didn't swim or wade, due to the prevalence of shark
>attacks in the area.
Shark attacks kill fewer people than lightning does each year. You should
have
gone in the water. BTW, did you drive to the beach? That is much more
dangerous
that swimming in the ocean as well.
>
>Jim Moore (j#d#.mo...@canrem.com)
>
Troy Kelley
Troy Kelley
Date: 13 Jun 1995 02:53:04 GMT
In article <3riuig$9...@pandora.sdsu.edu> Drew Talley,
tal...@sunstroke.sdsu.edu writes:
>As you point out below, none of this is terribly pivotal for the
>argument at hand. What is odd is your willingness to state
>with such certainty things which are simply not true, and which
>a nominal amount of investigating would have informed you.
>
>: Besides, crocodiles living in salt water, even though you seem to latch
>: on to this
>: issue rather quickly, is not the real issue for this news group. I was
>: not
>: implying that an aquatic environment was free from predators. I was
>: merely
>: pointing out that given our many physical deficiencies, which I am not
>: going to
>: list again, we must have evolved in a relatively safe environment. We
>: may have
>
>Drew
OK, OK.. Drew, Jim... you were right, I was wrong. Crocodiles can live
in water that containes various levels of salt. I made a mistake. I
shouldn't have said "I know crocodiles don't live in salt water", I made
a mistake.
I guess I should have typed, "you aren't likely to find crocodiles
swimming around in the open ocean with sharks" but I didn't. Or I should
have said, "you aren't likely to find crocodiles at the beach, but more
likely in rivers or streams." Or maybe I should have said "Crocodiles are
brackish animals and have varying tolerances to salt water".
Now... since this issue of crocodile tolerance to salt is out of the way,
can we please get back to the issue of AAT, or is that all but forgotten?
Troy Kelley
HARRY R. ERWIN
environment was fresh-water, rather than salt-water. Since the major
alternative (the wooded savanna ape) was also tied to water, there appears
to be a compromise available--an ape specialized for life in gallery
forests, with arboreal, terrestrial, and semi-aquatic components to its
substratum adaptation. Is there a way of testing this? Are there species
that people can identify with comparable adaptations? (I have a few in
mind, myself.)
--
Harry Erwin
Internet: her...@gmu.edu
Home Page: http://osf1.gmu.edu/~herwin
Drew Talley
: Yes, but I never said anything about the sea shore. Personnally, I think
: most
: of the aquatic phases took place in fresh water rivers, lakes and
: streams. It
: is possible that some swimming, diving, foraging did occur in the ocean,
: but this
: is not good drinking water, so there must have been fresh water nearby.
For example, an estuary?
[deletia]
: >
: >JM> Safe? From
: >JM> crocs and sharks we can't even see approaching? And which don't
: >JM> respond
: >JM> to human and chimpanzee threat displays (as big cats and other land
: >JM> predators do)?
: >
: >Tk> And besides that, I don't think crocodiles like salt water, in fact,
: I
: >Tk> know that they don't live in salt water.
: >
[existence of croc which swims in the ocean mentioned]
: The estuarian crocodile lives in ESTUARIES which are BRACKISH; or
: mixtures of some
: salt with but mostly fresh water. If these crocodiles are exposed to the
Okay, if I may enter in here again...while I know almost _nothing_
about anthropology, I find the lively debate here entertaining. On
the other hand, if your pronouncements about anthro are as informed
as those about crocs and estuaries, I think you'll have some trouble
defending the AAH.
First off, estuaries are indeed mixtures of salt and fresh water,
but to contend thaT they are "mostly fresh water" is simply wrong.
The salinity in an estuary changes both seasonally and tidally,
and can range from pure freshwater to pure saltwater depending
on depth, location, and phase of those temporal changes.
: kinds of
: salt levels found in the ocean for a long enough period of time, they
: will die.
Again, this is not true (depending on what you think qualifies as
a "long enough time". Certainly, as has been pointed out to you,
they can swim into the open ocean for miles...easily long enough to move
up the coast a bit and snack on an ape, where available.
As you point out below, none of this is terribly pivotal for the
argument at hand. What is odd is your willingness to state
with such certainty things which are simply not true, and which
a nominal amount of investigating would have informed you.
: Besides, crocodiles living in salt water, even though you seem to latch
: on to this
: issue rather quickly, is not the real issue for this news group. I was
: not
: implying that an aquatic environment was free from predators. I was
: merely
: pointing out that given our many physical deficiencies, which I am not
: going to
: list again, we must have evolved in a relatively safe environment. We
: may have
: >
: >Tk> Haven't you ever been to the beach?
: >Tk> Troy Kelley
: >
: >Yes, I have, but didn't swim or wade, due to the prevalence of shark
: >attacks in the area.
: Shark attacks kill fewer people than lightning does each year. You should
: have
: gone in the water. BTW, did you drive to the beach? That is much more
: dangerous
: that swimming in the ocean as well.
Drew
tal...@sunstroke.sdsu.edu
or
dta...@ucsd.edu
: >Jim Moore (j#d#.mo...@canrem.com)
: >
: Troy Kelley
J. Moore
JM> >pressure from non-human predators.
Tk> The fact is, chimpazees have very few natural (non-human) predators in
Tk> the wild and will live to a ripe old age in the wild.
Odd that you manage to suggest that, despite the fact that chimpanzees
manage to deal reasonably well with their potential predators, such as
lions and leopards, early hominids of similar size and brainpower would
be incapable of doing so.
JM> You gave a quote about how much water can be lost by active humans in
JM> the desert, which has nothing whatsoever to do with australopithecines
JM> unless they were in the desert. So your quote has nothing whatsoever
JM> to do with the subject at hand. (Question: How much water would, say, a
JM> wildebeest use in "an hour of walking in a hot day in the desert"?
JM> Answer: who cares? the desert has nothing to do with its actual
JM> habitat.)
Tk> The point was still that hominids do not conserve water very well, IN
Tk> ANY KIND OF HABITAT. I understand that they do not live in the desert
Tk> but I was merely pointing to their unusually high water consumption
Tk> rates. Did I not make that clear?
All that matters is whether or not they do *well enough*; that's how
evolution works. We see that in fact australopithecines did well enough
to survive in their environment for millions and millions of years. And
in fact even chimpanzees do well enough in relatively dry areas, similar
to those used by australopithecines.
Tk> If you really think I don't understand "how walking in the desert
Tk> differs from foraging and resting in a wooded savannah mosaic
Tk> environment" then I don't think you understood the point I was trying
Tk> to make at all.
Your point was, and is, irrelevant to the subject of australopithecine
adaption to their environment. Contrary to what you continually insist,
they just flat out worked in that environment; well enough to last there
for millions and millions of years.
Tk> > I don't think there is really any question, no matter what quote you
Tk> > come up with, that the susceptibility of early hominids to
Tk> > dehydration
Tk> > was probably pretty high. If you look at any other creature on the
Tk> > savanna, the ways in which they conserve water resources are far
Tk> > superior to the human/pre-human model. Their body temperatures are
Tk> > generally higher, they allow their internal body temperatures to
Tk> > rise in response to heat and they don't sweat, they pant.
Evolution works on what is there; it can't just build a whole new system
from scratch. Humans are primates, they evolved from primates, not from
antelopes, or pigs, or dogs. The fact that they use different physical
structures to accomplish similar ends compared to some other animals in
similar environments is not evidence that they didn't live there. In
fact, we know that they *did* live there, so whatever system they used
obviously worked well enough, regardless of whether or not other systems
worked "better". The "better" is in quotes because one problem with
using a physical adatation as a "solution to an environmental problem"
is that it almost inevitably reduces your options as a species. This
isn't a problem for a species that stays put in an environment that
changes slowly, but as it turns out for humans, it was yet another lucky
break in our evolutionary past that we didn't have such a gross
morphological adaptation to limit us.
JM> >And yet they *were* there; oh, not in the treeless and waterless
JM> >savannah that you imagine, but in the actual savannah environment that
JM> >existed in reality. And they were there for millions and millions of
JM> >years, which fact even the AAH accepts. So it is obvious that they
JM> >could and in fact did live and indeed thrive there.
Tk> Yes, they thrived in an environment that had the necessary aquatic
Tk> resources in order to replenish any fluids lost during the hot day.
Tk> I think you are still missing the point here. The AAH argument is that
Tk> if hominids
Tk> evolved EXCLUSIVELY in a savanna environment, then why don't they
Tk> conserve water
Tk> resources as well as other savanna creatures?
As I pointed out above, you can't just evolve whatever "takes your
fancy"; evolution works with what is there in the organism. So no, we
didn't survive there like antelopes do, or like warthogs, or by
burrowing and coming out at night, or by digging into the ground and
popping out every few months after the rains fall, or by any of the many
*different* ways that animals survived and still survive in that
environment -- we did it our way. (Everybody sing!)
Tk> Yes, but I never said anything about the sea shore. Personnally, I think
Tk> most
Tk> of the aquatic phases took place in fresh water rivers, lakes and
Tk> streams.
Tk> The estuarian crocodile lives in ESTUARIES which are BRACKISH; or
Tk> mixtures of some
Tk> salt with but mostly fresh water. If these crocodiles are exposed to
Tk> the kinds of
Tk> salt levels found in the ocean for a long enough period of time, they
Tk> will die.
As has been pointed out to you, both recently and several times
previously, you are incorrect.
Tk> Besides, crocodiles living in salt water, even though you seem to latch
Tk> on to this
Tk> issue rather quickly, is not the real issue for this news group.
I bring it up because a basic tenet of the AAH has been that "the
savannah" is full of dangerous predators, and the oceans (swamps,
streams, rivers, lakes, etc.) are not. The fact is that not only are
those waters full of dangerous predators, the predators there are also
demonstrably not as easy to see and do not respond to bluff and threats
as the major land-based predators [of large primates] demonstrably do.
Tk> I was not
Tk> implying that an aquatic environment was free from predators. I was
Tk> merely
Tk> pointing out that given our many physical deficiencies, which I am not
Tk> going to
Tk> list again, we must have evolved in a relatively safe environment. We
Tk> may have
Tk> developed defensive strategies to help avoid crocodiles. And I have
Tk> stated in this
Tk> news group before, that I would imagine it would be easier to deal with
Tk> crocodiles
Tk> as a predator than it would be to deal with lions, or big cats on the
Tk> open plains.
And here you make exactly that bogus point, contrary to fact.
Tk> The first reason is because crocodiles lay their eggs in shallow nests
Tk> around the
Tk> edges of their aquatic environment and do very little to defend these
Tk> nests.
Tk> These eggs would make a very good meal for early hominids and it would
Tk> be an
Tk> effective way to control the population of crocodiles as a whole.
The fact that crocodiles thrived in massive numbers along every African
waterway until extremely recently convincingly demonstrates that their
population wasn't well enough controlled to keep them from being a
constant danger to anything of reasonable size which enters the water
(fresh or salt).
Tk> I doubt if early hominids would have any chance of making a meal
Tk> out of lion cubs or leopard kittens.
Judging from the chimp actions at the leopard den at Mahale, I don't
think they would make a meal of them either. The chimps didn't eat the
leopard cub, they just killed it.
Tk> Secondly, crocodiles are dumb. They are much dumber than
Tk> lions, and I
Tk> would imagine that a defensive strategy could be developed to deal with
Tk> them after some examination of their habits.
Sure: stay out of the water. Quite effective, and easy to figure out
too.
It's their stupidity that makes them so hard to deal with. They just
don't respond well to threats, as the relatively smart mammalian
predators do.
Tk> >Tk> Haven't you ever been to the beach?
Tk> >Tk> Troy Kelley
JM> >Yes, I have, but didn't swim or wade, due to the prevalence of shark
JM> >attacks in the area.
Tk> Shark attacks kill fewer people than lightning does each year. You
Tk> should have
Tk> gone in the water. BTW, did you drive to the beach? That is much more
Tk> dangerous that swimming in the ocean as well.
Tk> Troy Kelley
Perhaps if *you're* driving. When driving, as with land-based mammalian
predators, you have some control over the situation (well, *I* do, anyway).
If you keep your wits about you, you can usually see trouble coming and
therefore take effective steps to avoid it. With sharks as with
crocodiles, your chances of seeing the trouble coming are greatly
reduced, and your chances of doing something about it once it arrives
are virtually nil.
J. Moore
He> environment was fresh-water, rather than salt-water. Since the major
He> alternative (the wooded savanna ape) was also tied to water, there
He> appears to be a compromise available--an ape specialized for life in
He> gallery forests, with arboreal, terrestrial, and semi-aquatic components
He> to its substratum adaptation. Is there a way of testing this? Are there
He> species that people can identify with comparable adaptations? (I have a
He> few in mind, myself.)
He> Harry Erwin
Some gorillas, various macaques and the proboscis monkey spend
varying amounts of time in all those places, but show none of the
supposed AAH adatations. They utilise common ape and monkey locomotor
behavior (a combination of quadrapedalism, brachiation, and bipedalism)
in each of these places. All are overwhelmingly quadrapedal on the
ground and in the water, despite claims by some AAH proponents that they
inevitably effect bipdal posture when in the water.
Various environments have been suggested by different AAH proponents;
all state that a major reason that these water environments were
necessary for the evolution of bipedalism is to help support the body
weight of the animal. Note that this necessarily means that the animal
must be well over waist deep in the water during much of the time that
it isn't sitting or lying. Knee-deep water isn't going to help support
body weight. Another major reason used is the claim that this
chest-deep water environment is much safer than being out in a
relatively open area where you have a chance to spot predators, hence
the other post(s) on the subject of predators.
J. Moore
Tk> >with such certainty things which are simply not true, and which
Tk> >a nominal amount of investigating would have informed you.
Tk> >
Tk> OK, OK.. Drew, Jim... you were right, I was wrong. Crocodiles can live
Tk> in water that containes various levels of salt. I made a mistake. I
Tk> shouldn't have said "I know crocodiles don't live in salt water", I made
Tk> a mistake.
Tk> I guess I should have typed, "you aren't likely to find crocodiles
Tk> swimming around in the open ocean with sharks" but I didn't. Or I
Tk> should have said, "you aren't likely to find crocodiles at the beach,
Tk> but more likely in rivers or streams."
If you had typed any of those things, you would also have been wrong.
Why not stick to writing what you know (I know, your posts would be too
short ;-), or, better yet, actually do some research before you make
wild statements, and actually look at both sides of an argument and try,
just try, to learn something along the way.
Tk> Now... since this issue of crocodile tolerance to salt is out of the
Tk> way, can we please get back to the issue of AAT, or is that all but
Tk> forgotten?
Tk> Troy Kelley
That depends, are you going to try and learn from posts, and perhaps do
some reading other than AAH supporters? If you aren't, you're doomed to
having people jump on your misstatements and misunderstandings just like
they did this time.
Cameron Laird
HARRY R. ERWIN <her...@osf1.gmu.edu> wrote:
>A clarification of at least one person's version of the AAT is that the
>to be a compromise available--an ape specialized for life in gallery
>forests, with arboreal, terrestrial, and semi-aquatic components to its
>substratum adaptation. Is there a way of testing this? Are there species
>that people can identify with comparable adaptations? (I have a few in
>mind, myself.)
.
.
.
I have no answers to those questions, so I'll ask my own.
One of the raps on Elaine Morgan is that she doesn't submit to
peer review. I see that
Morgan, Elaine
1995 The Descent of the Child: Human Evolution
from a New Perspective. Oxford University
Press
is now available. I haven't had one in my hands, but Oxford
U Pr in the past certainly has been a place that exercises
editorial oversight as responsibly as any other scientific
publisher. I'm curious to learn what the new perspective is.
What I really want: I think Oxf U Pr ought to send review
copies to Danny and Phil, and then we'll all meet back here
in a month.
--
Cameron Laird http://starbase.neosoft.com/~claird/home.html
cla...@Neosoft.com +1 713 267 7966
cla...@litwin.com +1 713 996 8546
Xiaoguang Zhang ~{UEO~9b~}
showed the amazing skills and coordination of new born infants under
water. It would be hard to convince me that these skills were simply
reflexes developed on land, especially the reflex of hoding breath.
Then it hit me. Is it possible, that at one point our ancestors were
living in a swamp, rather than savanna, where there was waist-high
water? This would probably force bipedalism, since anyone trying to
walk with hands would have his nose under water. Swimming might not
have been a viable alternative, since this period was probably too
short for an efficient swimmer to develop (there might be better
reasons such as food source, etc.). However, think about the infants
that were born in the water. They must know how to swim! They probably
clung to their mothers most of the time, but occasionly they might
fall into the water, and must be able to swim back to their mothers.
Is this idea crazy?
Troy Kelley
Date: Fri, 16 Jun 95 09:44:00 -0500
In article <60.1761.72...@canrem.com> J. Moore,
j#d#.mo...@canrem.com writes:
>Tk> Now... since this issue of crocodile tolerance to salt is out of the
>Tk> way, can we please get back to the issue of AAT, or is that all but
>Tk> forgotten?
>Tk> Troy Kelley
>
>That depends, are you going to try and learn from posts, and perhaps do
>some reading other than AAH supporters? If you aren't, you're doomed to
>having people jump on your misstatements and misunderstandings just like
>they did this time.
>
>Jim Moore (j#d#.mo...@canrem.com)
>
Jeeezzzee.. I try and be nice and conciliatory and I just get another
blast from your obnoxious, self-righteous crap.
>Tk> I guess I should have typed, "you aren't likely to find crocodiles
>Tk> swimming around in the open ocean with sharks" but I didn't. Or I
>Tk> should have said, "you aren't likely to find crocodiles at the beach,
>Tk> but more likely in rivers or streams."
>
>If you had typed any of those things, you would also have been wrong.
OK, Jim, now it is your turn to do a little reserch. So PLEASE do tell
me your reference that says "You are very likely to find crocodiles
swimming around in the open ocean with sharks" and show me how I was
"wrong". I am eagerly awaiting your reply, because I just really love
when you prove to everyone your expansive knowledge on all matters of
aquatic animal behaviour.
If you do not post any references that say that crocodiles "are likely
to be found swimming around in the open ocean with sharks" I will assume
that I was right and you were wrong. BTW, I mean crocodiles in GENERAL,
not one or two species that is swimming across a oceanic area to a
different habitat. Also, notice I did say OPEN ocean, this means far
away from the shorelines or costal areas, in otherwords in the MIDDLE of
the ocean.
Just so there is no confusion as to how you are going to show me "if [I]
had typed any of those things, [I] would also have been wrong".
BTW, I would like to formally apologize to this news group for wasting
bandwith on crocodile habitat, but I feel this is getting personnel and I
must defend myself from blatantly obnoxious criticism.
Troy Kelley
J. Moore
Tk> >Tk> forgotten?
Tk> >Tk> Troy Kelley
Tk> >
JM> That depends, are you going to try and learn from posts, and perhaps do
JM> some reading other than AAH supporters? If you aren't, you're doomed
JM> to having people jump on your misstatements and misunderstandings just
JM> like they did this time.
JM>
JM> Jim Moore (j#d#.mo...@canrem.com)
Tk> Jeeezzzee.. I try and be nice and conciliatory and I just get another
Tk> blast from your obnoxious, self-righteous crap.
It's just stating a fact, Troy. If you don't get some sort of weird
kick out of people constantly pointing out that you're posting wrong
information (I'll assume your reaction shows that you don't get a kick
from it), you'll have to do some research first. Even when you made
your apologetic post, you added yet *more* incorrect information,
without any signs of having done any of the fairly easy research that
would've allowed you to post correct information. If you do this
continually, you're guaranteed to get replies like mine, or worse.
Tk> > I guess I should have typed, "you aren't likely to find crocodiles
Tk> > swimming around in the open ocean with sharks" but I didn't. Or I
Tk> > should have said, "you aren't likely to find crocodiles at the
Tk> > beach, but more likely in rivers or streams."
Tk> >
JM> If you had typed any of those things, you would also have been wrong.
Tk> OK, Jim, now it is your turn to do a little reserch. So PLEASE do tell
Tk> me your reference that says "You are very likely to find crocodiles
Tk> swimming around in the open ocean with sharks" and show me how I was
Tk> "wrong". I am eagerly awaiting your reply, because I just really love
Tk> when you prove to everyone your expansive knowledge on all matters of
Tk> aquatic animal behaviour.
Tk> If you do not post any references that say that crocodiles "are likely
Tk> to be found swimming around in the open ocean with sharks" I will assume
Tk> that I was right and you were wrong. BTW, I mean crocodiles in GENERAL,
Tk> not one or two species that is swimming across a oceanic area to a
Tk> different habitat. Also, notice I did say OPEN ocean, this means far
Tk> away from the shorelines or costal areas, in otherwords in the MIDDLE of
Tk> the ocean.
Why wouldn't just one species do? No, crocodiles "in general" do not
swim in the ocean, and I must point out that "open ocean" and "in the
middle of the ocean" are rather different (oceans are big). BTW, I
noticed you dropped your "at the beach" reference -- good idea. I
should apologise and say simply that, although Indopacific Crocodiles
can and do swim into the open ocean at some distance from land, this
isn't nearly as common as finding them "at the beach". Which,
incidentally, is where the putative aquatic hominid was to be found.
Tk> Just so there is no confusion as to how you are going to show me "if
Tk> [I] had typed any of those things, [I] would also have been wrong".
Tk> BTW, I would like to formally apologize to this news group for wasting
Tk> bandwith on crocodile habitat, but I feel this is getting personnel and
Tk> I must defend myself from blatantly obnoxious criticism.
Tk> Troy Kelley
Crocodile habitat is in fact crucial to discussions of the AAH, as any
account of human evolution must contend with how our ancestors coped
with dangerous predators, and I'll post on it shortly.
Jim Moore (j#d#.mo...@canrem.com)
* Q-Blue 2.0 *
Sir CPU
Date: Thu, 15 Jun 95 09:01:00 -0500
Message-ID: <60.1747.72...@canrem.com>
I would like to respond to some of your previous posts.
JM> >You are again incorrect when you state that chimpanzees are not under
JM> >pressure from non-human predators.
Tk> The fact is, chimpazees have very few natural (non-human) predators in
Tk> the wild and will live to a ripe old age in the wild.
-Odd that you manage to suggest that, despite the fact that chimpanzees
-manage to deal reasonably well with their potential predators, such as
-lions and leopards, early hominids of similar size and brainpower would
-be incapable of doing so.
Well, I think chimps have a better opportunity to climb trees in the
wooded environment which they live. I think that if early hominids were
out on the open savanna, as the savanna theory states, they would have
much less of a chance to escape from a predator, especially a lion, to a
tree.
JM> You gave a quote about how much water can be lost by active humans in
JM> the desert, which has nothing whatsoever to do with australopithecines
JM> unless they were in the desert. So your quote has nothing whatsoever
JM> to do with the subject at hand. (Question: How much water would, say,
a
JM> wildebeest use in "an hour of walking in a hot day in the desert"?
JM> Answer: who cares? the desert has nothing to do with its actual
JM> habitat.)
Tk> The point was still that hominids do not conserve water very well, IN
Tk> ANY KIND OF HABITAT. I understand that they do not live in the desert
Tk> but I was merely pointing to their unusually high water consumption
Tk> rates. Did I not make that clear?
-All that matters is whether or not they do *well enough*; that's how
-evolution works. We see that in fact australopithecines did well enough
-to survive in their environment for millions and millions of years. And
-in fact even chimpanzees do well enough in relatively dry areas, similar
-to those used by australopithecines.
The point is, however, if hominids were evolving on the savanna for the
millions of years that they were supposedly, how come their evolution
didn't bring them up to the level of other savanna creatures. It is that
simple. I mean, don't you find it the least bit odd that the human body
temperature of 98 degrees is more like that of a dolphin or a whale than
that of other savanna creatures? And don't you find it odd that we expend
a tremendous amount of energy and resouces to keep our body temperature
constant, again like aquatic creatures, instead of allowing our internal
body temperature to rise? Again, if we were on the savanna for the
millions of years as you say, and did not have an interviening period of
"aquatic-ness", instead evolving with the other savanna creatures, why
then did we not end up evolving the same way?
Tk> If you really think I don't understand "how walking in the desert
Tk> differs from foraging and resting in a wooded savannah mosaic
Tk> environment" then I don't think you understood the point I was trying
Tk> to make at all.
-Your point was, and is, irrelevant to the subject of australopithecine
-adaption to their environment. Contrary to what you continually insist,
-they just flat out worked in that environment; well enough to last there
-for millions and millions of years.
You point of "well they were there, on the savanna, and they mananged to
survive well enough to get us to were we are today"; I don't think is a
very good one. Sure we were there, but we ended up taking a different
evolutionary path from the majority of animals there, now the question is
why? If you want to say, "well we did, and we made it ok, and that is
that, fine". But as a scientist, don't the peculuarities of our
anotomical structures make you wonder what causes us to be that way? And
then look for a SIMPLE explaination to cover all aspects of our unusual
physical structures?
Tk> > I don't think there is really any question, no matter what quote you
Tk> > come up with, that the susceptibility of early hominids to
Tk> > dehydration
Tk> > was probably pretty high. If you look at any other creature on the
Tk> > savanna, the ways in which they conserve water resources are far
Tk> > superior to the human/pre-human model. Their body temperatures are
Tk> > generally higher, they allow their internal body temperatures to
Tk> > rise in response to heat and they don't sweat, they pant.
-Evolution works on what is there; it can't just build a whole new system
-from scratch.
I agree. And this is why I think you see the strange human configuration.
Because evolution worked on an aquatic ape that was suddenly living on the
african plains.
-As I pointed out above, you can't just evolve whatever "takes your
-fancy"; evolution works with what is there in the organism. So no, we
-didn't survive there like antelopes do, or like warthogs, or by
-burrowing and coming out at night, or by digging into the ground and
Again, I think you are supporting my claim again. Evolution worked with
what it had in the organism, and aquatic organism, and came up with some
unusual strategies to cope with life on the savanna.
This is not a good arguement to defend our evolution on the savanna. To
say we were there, and we made due with our evolutionary circumstances,
does not cover the unusual aspects of our evolution that separate us from
other savanna creatures. I think the AAT goes a long way to help explain
these peculuarities, even if I don't know enough about crocodile habitats.
Troy Kelley
David L Burkhead
Subject: Re: Bipedalism and other factors
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In article <3sabc8$s...@newsbf02.news.aol.com> sir...@aol.com (Sir CPU) writes:
[ 8< Chimpanzees and natural predators >8 ]
>
>-Odd that you manage to suggest that, despite the fact that chimpanzees
>-manage to deal reasonably well with their potential predators, such as
>-lions and leopards, early hominids of similar size and brainpower would
>-be incapable of doing so.
>
>Well, I think chimps have a better opportunity to climb trees in the
>wooded environment which they live. I think that if early hominids were
>out on the open savanna, as the savanna theory states, they would have
>much less of a chance to escape from a predator, especially a lion, to a
>tree.
Several things here. First, climbing trees is not a terribly
effective escape strategy from leopards (a more serious threat in
wooded environs than lions, which are savanna creatures). Leopards
climb quite well, and being lighter than the chimps, they can travel
onto any branch which will support a chimp's weight. But that's
really a side issue. Check how chimpanzees _actually deal_ with
leopards. The footage I have seen did _not_ involve the chimps
fleeing, at least not all of them. A group of them gathered to throw
sticks and stones at the leopard to drive it away.
Sigh. This point has been answered _repeatedly_. Evolution
works with what's at hand. Pre-humans did not have the same starting
point as other savanna creatures. Thus, to expect the same results is
fatuous nonsense. All that matters is if human survival mechanisms
worked _well enough_. They patently did since they _did_ survive for
millions of years on the savanna. This savanna period also happened
_after_ any postulated aquatic period, so your arguments about
"intervening period of "aquatic-ness" is totally empty. There's no
_time_ after the known savanna and later periods for this hypothetical
aquatic phase.
Why don't humans let their body temperature rise? My guess would
be because we don't have large snouts to keep the _brain_ cool (as do
other large savanna mammals) and so have to keep the entire body cool.
Why the "coincidence" of body temperature? Well, why not provide some
_data_ on that? Just what body temperatures are found in various
animals--woodland primates, savanna dwelling large mammals, aquatic
mammals. A vague, arm-wavey "more like aquatic animals" says nothing
of substance.
>
>Tk> If you really think I don't understand "how walking in the desert
>Tk> differs from foraging and resting in a wooded savannah mosaic
>Tk> environment" then I don't think you understood the point I was trying
>Tk> to make at all.
>
>-Your point was, and is, irrelevant to the subject of australopithecine
>-adaption to their environment. Contrary to what you continually insist,
>-they just flat out worked in that environment; well enough to last there
>-for millions and millions of years.
>
>You point of "well they were there, on the savanna, and they mananged to
>survive well enough to get us to were we are today"; I don't think is a
>very good one. Sure we were there, but we ended up taking a different
>evolutionary path from the majority of animals there, now the question is
>why? If you want to say, "well we did, and we made it ok, and that is
>that, fine". But as a scientist, don't the peculuarities of our
>anotomical structures make you wonder what causes us to be that way? And
>then look for a SIMPLE explaination to cover all aspects of our unusual
We "ended up taking a different evolutionary path" because we
started from a different point. As has been pointed out to you time
and again evolution works with the material at hand. (Okay, that's
anthropomorphising the process but it will work as a metaphor, I guess.)
>physical structures?
>
>Tk> > I don't think there is really any question, no matter what quote you
>Tk> > come up with, that the susceptibility of early hominids to
>Tk> > dehydration
>Tk> > was probably pretty high. If you look at any other creature on the
>Tk> > savanna, the ways in which they conserve water resources are far
>Tk> > superior to the human/pre-human model. Their body temperatures are
>Tk> > generally higher, they allow their internal body temperatures to
>Tk> > rise in response to heat and they don't sweat, they pant.
>
>-Evolution works on what is there; it can't just build a whole new system
>-from scratch.
>
>I agree. And this is why I think you see the strange human configuration.
>Because evolution worked on an aquatic ape that was suddenly living on the
>african plains.
Sorry, but "aquatic ape" is _still_ an unjustified assumption.
There is enough difference between woodland ape going savanna and
other savanna creatures that the different evolutionary path is
sufficiently explained that way. We have only assertions and
whole-cloth creations of hypotheses to claim otherwise.
>
>
>-As I pointed out above, you can't just evolve whatever "takes your
>-fancy"; evolution works with what is there in the organism. So no, we
>-didn't survive there like antelopes do, or like warthogs, or by
>-burrowing and coming out at night, or by digging into the ground and
>
>Again, I think you are supporting my claim again. Evolution worked with
>what it had in the organism, and aquatic organism, and came up with some
>unusual strategies to cope with life on the savanna.
No. He did nothing of the sort. "Different from other savanna
animals" (which leads to different solutions to survival problems)
does _not_ necessarily support _your_ particular claim.
> This is not a good arguement to defend our evolution on the savanna. To
>say we were there, and we made due with our evolutionary circumstances,
>does not cover the unusual aspects of our evolution that separate us from
>other savanna creatures. I think the AAT goes a long way to help explain
>these peculuarities, even if I don't know enough about crocodile habitats.
Not at all. AAH has some _serious_ problems. Main of these is
that it picks and chooses. There are enough properties of any living
thing that you can find cross correllations between different types.
Yet we have AAH making claims that are totally unsupported. For
instance, the claim is made that the aquatic phase is what led to our
becoming bipedal. Yet, when asked, its proponents cannot point to a
_single_ bipedal aquatic mammal. Not one. Where, then, did this
extraordinary claim come from? Whole cloth creation.
Likewise, the claim is made that an aquatic environment provided
a refuge from predators. This is nonsense. For one thing, the
weakness of humans in comparison with terrestrial predators (on a
purely physical level) is even worse for humans in water wrt _aquatic_
predators. I can (or could before my knees went to pot) run with a
speed 25-30% of the _fastest_ land predator. An olympic swimmer
would not make more than 5% of the fastest aquatic predators, and not
more than 10% of more "typical" predators. Then, in the water, it is more
difficult to see predators coming and avoid them. Likewise, it is more
difficult to band together to drive off a predator (as those chimps did).
Also, aquatic predators are _stupid_ and unwilling to be driven off by threat
displays (unlike land based mammals).
Plainly, the AAH doesn't hold water.
David L. Burkhead
r3d...@dax.cc.uakron.edu
d.bur...@genie.geis.com
--
Spacecub - The Artemis Project - Artemis Magazine
Box 831
Akron, OH 44309-0831
Alex Duncan
Dept. of Anthropology
University of Texas at Austin
Austin, TX 78712-1086
512-471-4206
adu...@mail.utexas.edu
I can't help but chime in here.
The fact that hominids are capable of maintaining a constant
temperature in a heat-stressing environment is evidence that we are well
adapted to that environment. There is often more than a single solution
to a given problem, and simply because we don't use the same mechanisms
that bovids and equids do to deal with a hot open ecosystem doesn't mean
we're not well-adapted to it.
In fact, it might be suggested that the hominid adaptation to
living in a heat-stressing environment is superior to that of other
critters that are out there. We can travel much longer distances in a
given time than most other savannah-dwelling critters, and there are many
accounts of humans "walking their prey to exhaustion" in the hot sun. A
bovid may be able to run fast for a short distance on a hot day, but it
can't run long. Ambush predation is one way to deal with this, and
"exhaustion predation" is another. Yes, there is a cost -- we can't
stray too far from the water hole (unless we use tools: canteen, gourd,
skin water-bag).
Another point -- there really isn't a lot of evidence that early
hominids were living strictly in a savannah environment. The faunal
remains associated w/ A. ramidus are definitely suggestive of a more
closed habitat, and much of the evidence for A. afarensis and A.
africanus also point to life in a mosaic habitat in which a number of
different microhabitats were available. A. boisei is found in
depositional environments that are indicative of wetter habitats than the
co-eval H. erectus. In fact, its not until the appearance of H. erectus
that we see good evidence for "good" adaptation to open habitats
(human-like intermembral index, 1.8 m stature, thin "equatorial" body
build).
And finally, a comment on leopards -- yes, they climb trees, but
they don't hunt in trees (their prey are almost exclusively terrestrial
animals).
Pat Dooley
>Some gorillas, various macaques and the proboscis monkey spend
>varying amounts of time in all those places, but show none of the
>supposed AAH adatations. They utilise common ape and monkey locomotor
>behavior (a combination of quadrapedalism, brachiation, and bipedalism)
>in each of these places. All are overwhelmingly quadrapedal on the
>ground and in the water, despite claims by some AAH proponents that they
>inevitably effect bipdal posture when in the water.
I didn't know gorillas spent much time in the water. A simple moat seems
to be enough to keep them confined at many zoos. Where did you get
that information?
I've seen plenty of information on Macaques wading into water. I've never
seen
anything about them going in to any depth on four legs. Where did you get
that information.
Proboscis monkeys are not often observed in the wild. I've not seen
anything
that suggests they are "overwhelming quadrupedal" in the water. Where did
you get that information?
>Various environments have been suggested by different AAH proponents;
>all state that a major reason that these water environments were
>necessary for the evolution of bipedalism is to help support the body
>weight of the animal. Note that this necessarily means that the animal
>must be well over waist deep in the water during much of the time that
>it isn't sitting or lying. Knee-deep water isn't going to help support
>body weight. Another major reason used is the claim that this
>chest-deep water environment is much safer than being out in a
>relatively open area where you have a chance to spot predators, hence
>the other post(s) on the subject of predators.
That "supporting weight" reason is a new one on me. Archimedes would
soon tell you that quadrupedal entry into the water would provide more
support.
What are the real advantages of wading compared to quadrupedalism?
1) Better vision across the surface of the water and back to land.
2) Lower energy usage compared to swimming.
3) Less disturbance of the water while looking for prey (.c.f. earlier
post on Bonobos wading in streams and catching small fish hiding
under floating leaves.)
Pat Dooley
Pat Dooley
of crocodiles, the predation of same upon AA, etc. etc.
1) At least one species of Crocodile found in Northern Australia is fully
salt
tolerant. They can, and do, take humans swimming in open water. (These
are big beasts, and fierce.)
2) Aboriginals make extensive use of water resources in the same areas
as salt water crocodiles without suffering from population destroying
predation. They know when and where it is safe to enter the water
and where not to. White toursists are the usual victims in the rare
cases
where a human is taken, usually because they ignore the signs telling
them to beware of crocodiles.
Primates in the chimpanzee class are usually good at figuring out where
danger lies, be it lions, leopards or crocodiles.
3) The argument that apes could not have adapted to an aquatic environment
because of sharks or crocodiles is bogus. Both predators have been
around
when many other mammal species made the transistion from land to
water.
The pioneers must have been pretty clumsy in the water during the
initial
stages of the transition, but they made it.
4) My understanding is that African crocodiles are not fully salt
tolerant. I also
believe that AAT proponents suggest the Sea of Afar as a likely site
for the
AA to evolve. Once this Sea was separated from the Indian Ocean/Red
Sea, it slowly evaporated over the course of a few milion years, just
as the
Red Sea is now doing. That implies increasing salinity and less
friendly
environment for crocodlies.
Pat Dooley
Pat Dooley
> The fact that hominids are capable of maintaining a constant
>temperature in a heat-stressing environment is evidence that we are well
>adapted to that environment. There is often more than a single solution
>to a given problem, and simply because we don't use the same mechanisms
>that bovids and equids do to deal with a hot open ecosystem doesn't mean
>we're not well-adapted to it.
> In fact, it might be suggested that the hominid adaptation to
>living in a heat-stressing environment is superior to that of other
>critters that are out there. We can travel much longer distances in a
>given time than most other savannah-dwelling critters, and there are many
>accounts of humans "walking their prey to exhaustion" in the hot sun. A
>bovid may be able to run fast for a short distance on a hot day, but it
>can't run long. Ambush predation is one way to deal with this, and
>"exhaustion predation" is another. Yes, there is a cost -- we can't
>stray too far from the water hole (unless we use tools: canteen, gourd,
>skin water-bag).
The pack hunters, such as the wild dog and hyena, fill the "exhaustion
predation" niche. Lions fill the ambush niche, to an extent. Was there
room for a 10 mph weaponless bipedal ape to go pack hunting on the
savannah? Doesn't compute for me.
The problem is that the range depends on the ability to carry water. That
requires a level of tool building sophistication that was not available
until
H. Erectus arrived on the scene; an event post dating the evolution of
bipedalism.
> Another point -- there really isn't a lot of evidence that early
>hominids were living strictly in a savannah environment. The faunal
>remains associated w/ A. ramidus are definitely suggestive of a more
>closed habitat, and much of the evidence for A. afarensis and A.
>africanus also point to life in a mosaic habitat in which a number of
>different microhabitats were available. A. boisei is found in
>depositional environments that are indicative of wetter habitats than the
>co-eval H. erectus. In fact, its not until the appearance of H. erectus
>that we see good evidence for "good" adaptation to open habitats
>(human-like intermembral index, 1.8 m stature, thin "equatorial" body
>build).
Which leads back to the $64k question. If bipedalism wasn't a savannah
adaptation, what was it?
Arboreal? The arms would be more orang like, and the legs much shorter.
Display? No sign of sexual dimorphism.
Temperature Regulation? But bipedalism didn't evolve on the savannah.
Speed? A new-born Gnu can out-run a mature human. You need a great 800m
time to survive on the savannah.
Tool carrying? Bipedalism predates tools.
Food gathering? Lots of problems with disadvantageous intermediate forms.
Wading & Swimming? Crazy notion, but it fits with some other oddities.
> And finally, a comment on leopards -- yes, they climb trees, but
>they don't hunt in trees (their prey are almost exclusively terrestrial
>animals).
But they often hunt from trees. The Tatung boy was, apparently, an early
victim.
Pat Dooley
Pat Dooley
>showed the amazing skills and coordination of new born infants under
>water. It would be hard to convince me that these skills were simply
>reflexes developed on land, especially the reflex of hoding breath.
>Then it hit me. Is it possible, that at one point our ancestors were
l>iving in a swamp, rather than savanna, where there was waist-high
>water? This would probably force bipedalism, since anyone trying to
>walk with hands would have his nose under water. Swimming might not
>have been a viable alternative, since this period was probably too
>short for an efficient swimmer to develop (there might be better
>reasons such as food source, etc.). However, think about the infants
>that were born in the water. They must know how to swim! They probably
>clung to their mothers most of the time, but occasionly they might
>fall into the water, and must be able to swim back to their mothers.
>
>Is this idea crazy?
Not according to Sir Alistair Hardy, Desmond Morris and Elaine Morgan.
You should read Morgans books, especially, "The Scars of Evolution."
Pat Dooley
Nicholas Rosen
<adu...@mail.utexas.edu> says:
>
>In article <3snsv4$c...@newsbf02.news.aol.com> Pat Dooley,>Are you nuts? Most body weight reconstructions indicate male A.
>afarensis were about twice as large as females. The same was probably
>true of all other australopithecine species as well, and possibly even
>earliest Homo (depending on how we slice up the habiline group).
What I think Pat meant is that there is no sign of sexual dimorphism
in bipedalism. Males were neither more nor less bipedal than females
of the same species.
>>> And finally, a comment on leopards -- yes, they climb trees, but
>>>they don't hunt in trees (their prey are almost exclusively terrestrial
>>>animals).
>>
>>But they often hunt from trees. The Tatung boy was, apparently, an early
>>victim.
>
>I assume you mean Taung? The fact that leopards hunt from trees would
>certainly encourage a pre-hominid to stay IN a tree.
I'm not so certain. Leopards may normally hunt FROM trees, but if a
creature on the leopard diet climbs a tree, will the leopard decline
the opportunity to eat it because that isn't the way a leopard
usually hunts?
Nicholas Rosen
Standard disclaimers apply.
J. Moore
JM> >varying amounts of time in all those places, but show none of the
JM> >supposed AAH adatations. They utilise common ape and monkey locomotor
JM> >behavior (a combination of quadrapedalism, brachiation, and bipedalism)
JM> >in each of these places. All are overwhelmingly quadrapedal on the
JM> >ground and in the water, despite claims by some AAH proponents that
JM> >they inevitably effect bipdal posture when in the water.
Pa> I didn't know gorillas spent much time in the water. A simple moat seems
Pa> to be enough to keep them confined at many zoos. Where did you get that
Pa> information?
"Much time"? You certainly have a knack for reading things into pharses
like "varying time" that just aren't there. Gorillas in the Congo and
Zaire sometimes forage in swampy clearings, where they effect typical
gorilla locomotion and feeding behavior. Sabater Pi reported this
around 1975, and there was even a Nature show on TV a couple of years
back that showed this behavior.
Pa> I've seen plenty of information on Macaques wading into water. I've
Pa> never seen
Pa> anything about them going in to any depth on four legs. Where did you
Pa> get that information.
Unless they are carrying things in both hands (or begging for food from
humans), they are quadrapedal unless the water would be over their heads.
Note that these examples of occasional bipedal behavior in shallow water
are identical to how they effect bipedal behavior on dry land, and so
offer no evidence for the contention of what I clearly said were:
JM> >claims by some AAH proponents that
JM> >they inevitably effect bipdal posture when in the water.
Pa> Proboscis monkeys are not often observed in the wild. I've not seen
Pa> anything
Pa> that suggests they are "overwhelming quadrupedal" in the water. Where
Pa> did you get that information?
You *could* try reading some books. But then you're apparently not even
reading the writings *by* AAT supporters. To whit:
JM> >Various environments have been suggested by different AAH proponents;
JM> >all state that a major reason that these water environments were
JM> >necessary for the evolution of bipedalism is to help support the body
JM> >weight of the animal. Note that this necessarily means that the animal
JM> >must be well over waist deep in the water during much of the time that
JM> >it isn't sitting or lying. Knee-deep water isn't going to help support
JM> >body weight. Another major reason used is the claim that this
JM> >chest-deep water environment is much safer than being out in a
JM> >relatively open area where you have a chance to spot predators, hence
JM> >the other post(s) on the subject of predators.
Pa> That "supporting weight" reason is a new one on me.
This a new one on me; an AAT supporter who hasn't even read the works of
the AAT proponents!
Pa> Archimedes would soon tell you that quadrupedal entry into the
Pa> water would provide more support.
I'm not gonna wait for Archimedes to rise form the dead and tell me
that; I've known it for years. The problem is, it's irrelevant.
Pa> What are the real advantages of wading compared to quadrupedalism?
This is a false dichotomy, or what Bateson would call a "confusion of
logical types"; "wading" and "quadrapedalism" are not, as you claim
here, mutually exclusive. Monkeys and apes which do go into water most
often do so quadrapedally.
Pa> 1) Better vision across the surface of the water and back to land.
If the water isn't over your head, you can see "back to land" just
fine with your head at the surface of the water. On land, however,
bipedalism for this purpose would be a huge advantage.
Pa> 2) Lower energy usage compared to swimming.
Refs, please. I've always found walking through water to be
energy-intensive, as water gives such much resistance. But please do
provide the references which contradict this impression.
Pa> 3) Less disturbance of the water while looking for prey (.c.f. earlier
Pa> post on Bonobos wading in streams and catching small fish hiding under
Pa> floating leaves.)
Pa> Pat Dooley
The AAT doesn't work if all you're claiming is that hominids
occasionally waded into ankle- or even knee-deep water; such behavior
requires no adaptations that are not those of a land-based primate.
So simple catching of fish in such shallow water provides no support for
the AAT's contentions that water allowed and even forced bipedalism
while land-based activities couldn't, and that our pattern of body hair
is an adaptation to intensive foraging and predator avoidance in water.
Perhaps you could explain how the AAT-hominids defended themselves
against fierce aquatic predators such as crocodiles and sharks.
Alex Duncan
>
>The pack hunters, such as the wild dog and hyena, fill the "exhaustion
>predation" niche. Lions fill the ambush niche, to an extent. Was there
>room for a 10 mph weaponless bipedal ape to go pack hunting on the
>savannah? Doesn't compute for me.
>
>The problem is that the range depends on the ability to carry water. That
>requires a level of tool building sophistication that was not available
>until
>H. Erectus arrived on the scene; an event post dating the evolution of
>bipedalism.
I may have entered this thread too late to fully understand the
arguments. Please clarify something: The AAT is offered as an
explanation for how hominids BECAME bipedal?
Yes, dogs and hyenas occupy the niche, but they don't necessarily
fill it. Hyenas are primarily nocturnal. That leaves the dogs out in
the day time, but does not mean that early humans couldn't also have
occupied that niche.
I wasn't suggesting that any hominids earlier than H. erectus
occupied this niche.
>
>> Another point -- there really isn't a lot of evidence that early
>>hominids were living strictly in a savannah environment. The faunal
>>remains associated w/ A. ramidus are definitely suggestive of a more
>>closed habitat, and much of the evidence for A. afarensis and A.
>>africanus also point to life in a mosaic habitat in which a number of
>>different microhabitats were available. A. boisei is found in
>>depositional environments that are indicative of wetter habitats than the
>>co-eval H. erectus. In fact, its not until the appearance of H. erectus
>>that we see good evidence for "good" adaptation to open habitats
>>(human-like intermembral index, 1.8 m stature, thin "equatorial" body
>>build).
>
>Which leads back to the $64k question. If bipedalism wasn't a savannah
>adaptation, what was it?
>
>Arboreal? The arms would be more orang like, and the legs much shorter.
How about this: hominids evolved from an ancestor that was so specialized
for an arboreal existence that its only effective mean of terrestrial
locomotion was bipedalism (see modern gibbons). In a fragmenting forest
environment, those pre-hominids that were most adept at moving from tree
to tree ON THE GROUND would have been selected for. An important thing
to note here is that this model doesn't suggest that pre-hominids adapted
bipedalism because living in open country was so wonderful. They did it
because they needed to cross open country from one patch of trees to the
next. As time went on, and aridification increased (e.g. terminal
Miocene climatic event) the patches between trees became progressively
larger and larger, selecting for more and more efficient bipeds.
Eventually the adaptation to crossing open ground became effective enough
that early hominids began other activities in open country (looking for
food, etc.).
>
>Display? No sign of sexual dimorphism.
Are you nuts? Most body weight reconstructions indicate male A.
afarensis were about twice as large as females. The same was probably
true of all other australopithecine species as well, and possibly even
earliest Homo (depending on how we slice up the habiline group).
>
>Temperature Regulation? But bipedalism didn't evolve on the savannah.
No, but it may have turned out to have the added benefit of helping temp.
regulation once hominids began routinely living in open country.
>
>Speed? A new-born Gnu can out-run a mature human. You need a great 800m
>time to survive on the savannah.
Or a complex social organization. A single hominid may have been easy
prey for a variety of savannah carnivores, but a group of cooperating
hominids would not.
>
>Tool carrying? Bipedalism predates tools.
Bipedalism predates tools that fossilize. Both humans and chimps use
tools, suggesting that this trait was present in the common ancestor of
humans and chimps, and thus, early hominids.
>
>Wading & Swimming? Crazy notion, but it fits with some other oddities.
I can think of no oddities that wading and swimming fit in with. Please
enlighten me. I'm not suggesting that early hominids didn't occasionally
enter the water, but to postulate an aquatic existence as the precursor
to all that is "hominid" flies in the face of all of the evidence I'm
aware of.
>
>> And finally, a comment on leopards -- yes, they climb trees, but
>>they don't hunt in trees (their prey are almost exclusively terrestrial
>>animals).
>
>But they often hunt from trees. The Tatung boy was, apparently, an early
>victim.
I assume you mean Taung? The fact that leopards hunt from trees would
certainly encourage a pre-hominid to stay IN a tree.
Alex Duncan
Phil Nicholls
>Jim Moore writes:
>>Some gorillas, various macaques and the proboscis monkey spend
>>varying amounts of time in all those places, but show none of the
>>supposed AAH adatations. They utilise common ape and monkey locomotor
>>behavior (a combination of quadrapedalism, brachiation, and bipedalism)
>>in each of these places. All are overwhelmingly quadrapedal on the
>>ground and in the water, despite claims by some AAH proponents that they
>>inevitably effect bipdal posture when in the water.
>I didn't know gorillas spent much time in the water. A simple moat seems
>to be enough to keep them confined at many zoos. Where did you get
>that information?
Lowland Gorillas wade into swamps on a regular basis. They are not as
well known as Mountain gorillas but a recent Nature special shows them
doing it rather clearly -- water up to their waste covering their
haunches.
>I've seen plenty of information on Macaques wading into water. I've never
>seen
>anything about them going in to any depth on four legs. Where did you get
>that information.
Macaques, in general, don't go into water so deep they have to stand
bipedally. Some do but the point is they show no special changes in
their muscluloskeletal systems.
>Proboscis monkeys are not often observed in the wild. I've not seen
>anything
>that suggests they are "overwhelming quadrupedal" in the water. Where did
>you get that information?
Kawabe, M. and Mano T. (1972) Ecology and Behavior of the wild
proboscis monkey (Nasalis larvatus, Wurmb) in Sabah, Malaysia,
PRIMATES 13:213-228.
>>Various environments have been suggested by different AAH proponents;
>>all state that a major reason that these water environments were
>>necessary for the evolution of bipedalism is to help support the body
>>weight of the animal. Note that this necessarily means that the animal
>>must be well over waist deep in the water during much of the time that
>>it isn't sitting or lying. Knee-deep water isn't going to help support
>>body weight. Another major reason used is the claim that this
>>chest-deep water environment is much safer than being out in a
>>relatively open area where you have a chance to spot predators, hence
>>the other post(s) on the subject of predators.
>That "supporting weight" reason is a new one on me. Archimedes would
>soon tell you that quadrupedal entry into the water would provide more
>support.
>What are the real advantages of wading compared to quadrupedalism?
>1) Better vision across the surface of the water and back to land.
Data?
>2) Lower energy usage compared to swimming.
Data?
>3) Less disturbance of the water while looking for prey (.c.f. earlier
>post on Bonobos wading in streams and catching small fish hiding
>under floating leaves.)
Bonobos wade into SHALLOW streams in ankle-deep water.
>Pat Dooley
==========================================================
Phil Nicholls "To ask a question you must first
pn...@globalone.net know most of the answer.
Semper Alouatta! - Robert Sheckley
Alex Duncan
ndr...@psuvm.psu.edu writes:
>>
>
>What I think Pat meant is that there is no sign of sexual dimorphism
>in bipedalism. Males were neither more nor less bipedal than females
>of the same species.
Are you sure about that? It may seem unlikely that males and females
would have different regimes of positional behaviors, but we do see such
things in modern gorillas and orangs. In both of these taxa, females are
more frequent arborealists than males.
See Stern & Susman (1983) Am. J. Phys. Anthrop. and Susman et al.
(1984) Folia Primatologia for a discussion of sexual dimorphism in
locomotor anatomy in A. afarensis. They suggest a greater frequency of
terrestrialism in males.
But really -- what do sexual differences in locomotion have to do
with display. I've never seen any hints that male and female chimps
differ significantly in locomotor behavior, but males display routinely
and more frequently than females.
>Leopards may normally hunt FROM trees, but if a
>creature on the leopard diet climbs a tree, will the leopard decline
>the opportunity to eat it because that isn't the way a leopard
>usually hunts?
I challenge you to find a single known instance of a leopard catching a
healthy baboon or chimpanzee IN A TREE. I'm not saying that it doesn't
happen, but it probably happens so rarely as to be insignificant.
Primates are much more adept in the arboreal substrate than leopards are.
Leopards are generally confined to the trunk and large proximal
branches. Primates (especially suspensory hominoids) are capable of
movement in the smaller distal branches where quadrupeds can't go.
A secondary and important point -- are we suggesting that primates
shouldn't climb trees because there are leopards there? This is getting
really ridiculous. You can count the number of terrestrial primate
species in Africa on the fingers of both hands. There are at least 50
species of primate in Africa (where the leopards are) that are almost
exclusively arboreal.
HARRY R. ERWIN
References: <3sabc8$s...@newsbf02.news.aol.com> <3snsv4$c...@newsbf02.news.aol.com> <3snsvk$d...@newsbf02.news.aol.com> <3snvuk$i...@geraldo.cc.utexas.edu>
Organization: George Mason University, Fairfax, Virginia, USA
Distribution: world
Subject: Re: Bipedalism and other factors
Newsgroups: sci.anthropology.paleo
References: <3sabc8$s...@newsbf02.news.aol.com> <3snsv4$c...@newsbf02.news.aol.com> <3snsvk$d...@newsbf02.news.aol.com> <3snvuk$i...@geraldo.cc.utexas.edu>
Organization: George Mason University, Fairfax, Virginia, USA
Distribution: world
Alex Duncan (adu...@mail.utexas.edu) wrote:
---trimmed---
: I may have entered this thread too late to fully understand the
: arguments. Please clarify something: The AAT is offered as an
: explanation for how hominids BECAME bipedal?
: Yes, dogs and hyenas occupy the niche, but they don't necessarily
: fill it. Hyenas are primarily nocturnal. That leaves the dogs out in
: the day time, but does not mean that early humans couldn't also have
: occupied that niche.
In fact, a biped would have partitioned this niche since it would have
been able to identify high-quality food sources at a longer distance than
the dogs.
: I wasn't suggesting that any hominids earlier than H. erectus
: occupied this niche.
My take as well.
: >
: >> Another point -- there really isn't a lot of evidence that early
: >>hominids were living strictly in a savannah environment. The faunal
: >>remains associated w/ A. ramidus are definitely suggestive of a more
: >>closed habitat, and much of the evidence for A. afarensis and A.
: >>africanus also point to life in a mosaic habitat in which a number of
: >>different microhabitats were available. A. boisei is found in
: >>depositional environments that are indicative of wetter habitats than the
: >>co-eval H. erectus. In fact, its not until the appearance of H. erectus
: >>that we see good evidence for "good" adaptation to open habitats
: >>(human-like intermembral index, 1.8 m stature, thin "equatorial" body
: >>build).
: >
: >Which leads back to the $64k question. If bipedalism wasn't a savannah
: >adaptation, what was it?
This reminds me of the current controversy about Acanthostega. It has
turned out that this relative/ancestor(?) of Icthyostega and the primitive
amphibians was obligately dependent on water--despite extremely primitive
limbs, it could not leave the water. Instead, it was apparently adapted to
predation in swamp environments where the use of fins to maintain one's
position would be detectable as pressure waves, but the use of hands and
feet would not.
Bipedalism could not have been a savannah adaptation because primitive
hominids couldn't make a living in the savannah. Too many other
adaptations had to be acquired first. It was an adaptation to something
else that preadapted the hominid (probably early Homo erectus) to move
into the savannah.
: >
: >Arboreal? The arms would be more orang like, and the legs much shorter.
: How about this: hominids evolved from an ancestor that was so specialized
: for an arboreal existence that its only effective mean of terrestrial
: locomotion was bipedalism (see modern gibbons). In a fragmenting forest
: environment, those pre-hominids that were most adept at moving from tree
: to tree ON THE GROUND would have been selected for. An important thing
: to note here is that this model doesn't suggest that pre-hominids adapted
: bipedalism because living in open country was so wonderful. They did it
: because they needed to cross open country from one patch of trees to the
: next. As time went on, and aridification increased (e.g. terminal
: Miocene climatic event) the patches between trees became progressively
: larger and larger, selecting for more and more efficient bipeds.
: Eventually the adaptation to crossing open ground became effective enough
: that early hominids began other activities in open country (looking for
: food, etc.).
I agree in general, but it sounds a little bit like Romer's scenario for
the emergence of the Icthyostegans onto the land. The ecological niche
occupied by these prehominids had to involve making a living in those
patchy forests. In deserts, bipeds have a longer search range than
quadrupeds of the same weight and lower energy costs than birds of the
same weight. The same would be the case (though less dominantly) in patchy
forests. I suspect the niche also involved climbing forest-edge trees to
the very top to get a good view of what was on the other side of the patch
of open land. I think Alex can work out the implications of this set of
selective forces.
: >
: >Display? No sign of sexual dimorphism.
: Are you nuts? Most body weight reconstructions indicate male A.
: afarensis were about twice as large as females. The same was probably
: true of all other australopithecine species as well, and possibly even
: earliest Homo (depending on how we slice up the habiline group).
Females 20-30 kg, males 40-50 seems to be the consensus, with some
workers estimating even lower weights (which are possible, since body
mass estimates depend on assumptions about the amount of muscle/fat/etc.
per unit volume). Weight dimorphism in the range 1.75-2.00 (i.e.,
extremely high).
---trimmed---
: >
: >Wading & Swimming? Crazy notion, but it fits with some other oddities.
: I can think of no oddities that wading and swimming fit in with. Please
: enlighten me. I'm not suggesting that early hominids didn't occasionally
: enter the water, but to postulate an aquatic existence as the precursor
: to all that is "hominid" flies in the face of all of the evidence I'm
: aware of.
It's easy to envision early hominids having some skill with water (i.e.,
behavioral adaptation), but without a great deal of skeletal adaptation in
that direction. Look at cats--tigers take to the water easily, while most
species avoid it. I suspect this can be tabled as having no strong
evidence in either direction. In any case, hominids probably did not
spend most of their time in the water. Not with limbs adapted to climbing
and bridging.
: >
: >> And finally, a comment on leopards -- yes, they climb trees, but
: >>they don't hunt in trees (their prey are almost exclusively terrestrial
: >>animals).
: >
: >But they often hunt from trees. The Tatung boy was, apparently, an early
: >victim.
: I assume you mean Taung? The fact that leopards hunt from trees would
: certainly encourage a pre-hominid to stay IN a tree.
Leopards use trees like I posit prehominids do--as bases for operations on
the ground. Given the relative weights and the arboreal quadrupedalism
seen in leopards, I suspect prehominids were fairly efficient at avoiding
a leopard if one came into their tree. Not only do their climbing and
bridging adaptations effectively double the space accessible to the
prehominids over equal-sized felids, but if the weight of the vulnerable
prehominids was sufficiently low relative to that of a leopard, they could
move out on branches or the main stem to regions of the tree that were
inaccessible to the leopard. Look at hoatzin behavior for some insight
into these issues.
Quick analysis: basic niche of leopards and prehominids was probably
similar, except that prehominids were more omnivorous. Since leopards are
quadrupedal, they need greater bodymass to be able to search at the same
rate on the ground, and are handicapped in their climbing to sighting
spots by that greater mass and their lack of grasping capability. Hence
prehominids had a greater search rate in a wooded savannah than any felid
(or canid). Group behavior that provided protection on the group against
carnivores would have allowed prehominids to maintain a larger population
in a patch of wooded savannah than felids could maintain. Canids could
maintain a larger population only if they were markedly less selective
than the prehominids in their feeding. That implies, by the way, that
leopards could not compete with prehominids except in areas of savannah
where the tree density was sufficiently low that leopards could exclude
prehominids from the available trees. You end up with four zones of
savannah:
1. treeless, where canids, birds, and large felids were dominant.
2. sparsely treed, where you found leopards,
3. moderately treed, where you found prehominids, and
4. heavily treed, where you found prechimps (since sighting range was not
the dominant selective force there).
Cheers --
Harry Erwin
Internet: her...@gmu.edu
Home Page: http://osf1.gmu.edu/~herwin (try a couple of times)
Barry Mennen
>The pack hunters, such as the wild dog and hyena, fill the
"exhaustion
>predation" niche. Lions fill the ambush niche, to an extent. Was there
>room for a 10 mph weaponless bipedal ape to go pack hunting on the
>savannah? Doesn't compute for me.
>time to survive on the savannah.
>
>
(tools)--wood doesn't fossilize too well--weaponless 10 mph
bipedalists?--weapons are what got us to where we are today--grow up!
Cheers
Barry
the ape man
Pat Dooley
>>I've seen plenty of information on Macaques wading into water. I've
never
>>seen
>>anything about them going in to any depth on four legs. Where did you
get
>>that information.
pn...@globalone.net (Phillip Nicholls) wrote:
>Macaques, in general, don't go into water so deep they have to stand
>bipedally. Some do but the point is they show no special changes in
>their muscluloskeletal systems.
Me:
And the wading is a relatively recent innovation for them. Evolution
doesn't
work that fast.
Me:
>>What are the real advantages of wading compared to quadrupedalism?
>>1) Better vision across the surface of the water and back to land.
Him:
>Data?
Me:
Try a little geometry, or trigonometry if common sense doesn't tell you
why.
Me:
>>2) Lower energy usage compared to swimming.
Him:
>Data?
Me:
How long can you tread water, compared to simply standing in it? How long
can you wade compared to swimming?
The energy efficiency of wading reduces as water depth increases. The
energy
cost of swimming is constant once the water is deep enough to sustain
swimming. For a bipedal ape, the point of equal efficiency is likely to
be between knee-deep and chest-deep. For a quadruped, the range within
which they can choose between swimming and wading is much more limited.
In circumstances in which wading is more efficient, whether that be
measured in terms of energy expenditure or food gathering efficiency,
primates often wade bipedally rather than swimming quadrupedally.
>>3) Less disturbance of the water while looking for prey (.c.f. earlier
>>post on Bonobos wading in streams and catching small fish hiding
>>under floating leaves.)
Him:
>Bonobos wade into SHALLOW streams in ankle-deep water.
Me:
It's a bit hard to tell from the reference you gave previously. However,
if the water was only ankle deep, there would have been no advantage
to the Bononbos wading bipedally to catch fish lurking amongst floating
leaves.
Pat Dooley
J. Moore
Pa> predation" niche. Lions fill the ambush niche, to an extent. Was there
Pa> room for a 10 mph weaponless bipedal ape to go pack hunting on the
Pa> savannah? Doesn't compute for me.
If you're going to talk about a transtional hominid, perhaps you could
try using some sort of example that actually has something to do with
how that hominid lived. Big game hunting seems to have begun no sooner
than at least 5-8 million years *after* the split from apes.
Pa> >different microhabitats were available. A. boisei is found in
Pa> >depositional environments that are indicative of wetter habitats than
Pa> the
Pa> >co-eval H. erectus. In fact, its not until the appearance of H.
Pa> erectus
Pa> >that we see good evidence for "good" adaptation to open habitats
Pa> >(human-like intermembral index, 1.8 m stature, thin "equatorial" body
Pa> >build).
Pa> Which leads back to the $64k question. If bipedalism wasn't a savannah
Pa> adaptation, what was it?
Why don't you just *try* reading some semi-current theory? Get rid of
your "treeless, waterless savannah" fixation and work with something
more accurate. You give some evidence above of knowing that the treeless,
waterless savannah you're using as a strawman versus the AAT is not
accurate.