Re: Bipedalism and other
J. Moore (j#d#.moore@canrem.com)
Tue, 27 Jun 95 13:17:00 -0500
JM> >Some gorillas, various macaques and the proboscis monkey spend
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.
Jim Moore (j#d#.moore@canrem.com)
* Q-Blue 2.0 *
|