Re: Dissecting the Aquatic Ape: Bipedalism

Paul Crowley (
Sun, 28 Jul 96 00:22:38 GMT

In article <4tb3b9$> "HARRY R. ERWIN" writes:

> The niche is large-bodied suspensory feeding in open-canopy forest. This
> differs from large-bodied suspensory feeding in closed-canopy forest in
> that you can't bridge from tree to tree (as can Pongo or Hylobates).
> Instead, you have to climb down out of the tree to move to another tree.

Do you really believe this? Or are you just repeating a formula?
I'm putting forward the hypothesis that predominantly ground-based
catarrhines and hominoids are a major part of the normal fauna of
open-canopy forests. They are now, and if you are going to maintain
that it was different in the past then the onus is on you to say why.
If you can't then I suggest that we should assume that our hominoid
ancestors have been predominantly ground-based for 20 Myr or more.

The fossil evidence is so patchy and so indeterminate, that it is
of little assistance.

> In relatively closed open-canopy forest, a bipedal stance doesn't give you
> useful early warning of attack.

Again: Do you really believe this? Or are you just repeating a
formula? Have the assumptions involved here ever been tested in
the real world? None of the accounts in Goodall where a chimp
or other primate is attacked, or ambushed, or where a group appears
threatened would seem to support them. Nearly all the lethal
attacks on vulnerable chimps, baboons, or other primates appear to
occur when a single victim is feeding or resting in a tree and the
attacking group moves silently on the ground to cut off all avenues
of escape.

Sounds, smells and other indications of presence are relied on
heavily. There are no (or very few) accounts of an attacker or
a victim standing tall (like a meercat) to see what's coming.

> That set of selective pressures leads to
> Pan and Gorilla. In more open forest, or in close forest if the understory
> is not overgrown, the height above ground of the sensory organs in a
> bipedal posture is useful in giving early warning of attack, and you get
> various hominids.

If you were in a forest with only a knife, afraid of being attacked
by leopards, chimps or gorillas, which you couldn't see but you
knew were there, what stance would you take? What stance do
soldiers on patrol in the jungle take, especially when they are
under threat? Come on, let's have a little bit of common sense
around here.