Re: tree-climbing hominids

David Froehlich (
Sun, 8 Oct 1995 17:21:31 -0500

On Sun, 8 Oct 1995, Paul Crowley wrote:

> I should have dealt with this last time. We are concerned with two forms
> of locomotion: quadrupedal and bipedal. There is effectively no half-way
> stage. (Obviously there must have been a transition, but it must have
> taken place under very special circumstances - which is why the AAT
> exists).

I have dealt with this in other posts but I will rephrase. The closest
living relatives of the hominids are the gibbon (obligate biped on flat
surfaces), orangutan (facultative biped), gorilla (facultative biped) and
chimpanzee (facultative biped). There are also numerous examples of
other facultative bipeds among the primates. Consequently, what is the
big deal? AAS rest on the unproven assumption that bipedality is a very
difficult form of locomotion. My contention is that there is no great
leap from hominoid to homonid. So I do not accept this basic premise
that there had to be some magical change produced by a evolutionary
period in a totally different environment.

> I cannot really "prove" this. It is self-evident that any viable animal
> must have an effective mode of locomotion. Being "partially bipedal" or
> "partially quadrupedal" is NOT viable (except under those very special
> circumstances). You simply have to think of your own anatomy. How

The above statment is the basic disconnect.

> could it be modified so that you were less than "fully bipedal" and yet
> still remain a creature that could thrive on the ground in Africa?

What do you think chimps do?

> I just don't buy this. Either they slept in the trees (like chimps) or
> they didn't. "Part-time life in the arboreal substrate" is empty BS.

Why is part time life in the trees more difficult to buy than an aquatic

David J. Froehlich Phone: 512-471-6088
Vertebrate Paleontology Laboratory Fax: 512-471-5973
J.J. Pickle Research Campus
The University of Texas, Austin, Texas 78712