Crowley lies again

Alex Duncan (
28 Nov 1995 02:21:27 GMT

In article <> Paul Crowley, writes:

PC> Sleeping in trees is not a human behaviour. No tribe anywhere
PC> is reputed to do it. There's a complete absence of any relevant
PC> instinctive behaviour. It's safe to conclude that homo erectus
PC> - with a very similar morphology was the same. How did it spend
PC> the night?
JM> You are again, as in a post of yours I just replied to, suggesting
JM> that the earliest transitional hominids were just like us; that
JM> there has been no evolutionary change between then and now.
PC>There is no such suggestion. I am, once again, seeking an answer from
PC>the paleoanthropologists on "When did our ancestors come down from the
PC>trees?" Could any question be more basic? Is there the remotest
PC>hope of getting an answer? Is PA in deep doo-doo?
PC>The PA consensus (insofar as a deep reluctance to face the issue could
PC>be called a "consensus") appears to be that the australopithecines
PC>in the trees. We don't. When was the change? When? When? When?
PC>No answer. No answer. No answer. No answer. No answer. No answer.

I am quite certain that I have addressed this issue previously, and I am
also quite certain that you (PC) have read it (thus the title of the
post). Please allow me to reiterate:

As far as we know, most australopithecine taxa have a morphology that
would be consistent with their use of arboreal resources. Despite the
protestations of Dr. Ohman, the consensus within the PA community is that
australopithecines slept in the trees. There are, of course, some
problematic aspects. While the postcranial skeletons of A. afarensis and
A. africanus are relatively well known, those of A. robustus and A.
boisei are poorly known, and so conclusions regarding their positional
behavior must be regarded as very tentative.

"H. habilis" is a problematic taxon as well. It seems to me that a
consensus is emerging that "H. habilis" sensu lato may be divided into
the 2 species H. habilis sensu stricto (e.g. ER 1813) and H. rudolfensis
(e.g. ER 1470). The smaller species, H. habilis, seems to have a
postcranial anatomy that is very similar to that of the
australopithecines, and may potentially be even more ape-like in some
features (see estimated humero-femoral indices for OH 62). H.
rudolfensis, on the other hand, may have been characterized by a more
human-like postcranial skeleton.

The postcranial skeleton of early African H. erectus is very well known,
and seems to be human-like in most relevant aspects.

So, to sum up: by the time of the origin of H. erectus (app. 1.8 Myr),
humans were pretty well out of the trees. It may have been earlier, but
currently the postcranial skeleton of the larger habiline taxa is too
poorly known to make any definitive statements.

So, in other words, here is your answer. It is an answer you have been
provided with before. Perhaps you should print this out so you can read
it when you're overwhelmed with ignorance. Perhaps you should read more
about PA than what you can find in Ms. Morgan's books.

Your suggestion that physical anthropologists approach this issue with
"deep reluctance" is downright dishonest. It is a very interesting
issue, and one that most anthropologists who deal with hominid evolution
are eager to address.

(And, by the way, your suggestion that there is a "complete absence of
relevant instinctive behavior" is misguided. Ever heard of the Babinski
reflex? It's one of the first expressed by newborn human infants.)

Alex Duncan
Dept. of Anthropology
University of Texas at Austin
Austin, TX 78712-1086