Re: An alternative to ST and AAT

Paul Crowley (
Mon, 18 Nov 96 11:40:56 GMT

In article <56np2r$> "Gerrit Hanenburg" writes:

> There's nothing wrong with Paul being right. Intellectual integrity
> requires that we sometimes have to acknowledge that someone else may
> be right. But I suspect that Paul just made a lucky guess that wasn't
> based on any biomechanical analysis (he wasn't able to give a
> reference when Phillip Bigelow asked for it). Sometimes a guess turns
> out to be right.

Thanks for the intellectual integrity and for the references.
It was not a lucky guess. My main source was a particularly
good lecturer at Liverpool University, Patrick Quiney, who gave
us a good imitation of how he thought Lucy walked. Also I have
read around and come across this implication several times.
But I don't have easy access to the University library so I can
rarely give references - not quickly anyway.

But any serious thought on Lucy's morphology should lead to
the same conclusion. If you can't stride, you must waddle.

Susan asked:
> How do you account for the Laetoli footprints then? 3.7myo and
> fully bipedal stride, there is even an arch in the foot, so not
> only did these hominids stride, they did so with shock absorbers
> developed in the foot.

I don't see how arches or putting the weight on the outside of
the foot or "shock absorbers" are necessarily incompatible with
a waddling gait. Also the Laetoli footprints are not clear;
they've been interpreted in many different ways; and there is
a great temptation to read a modern human gait into them.

On the wider issue I feel, in spite of Gerrit's reluctance and
evasions, we are making progress. If we focus hard on good
questions and insist on proper answers, they may eventually
emerge. To ask again:

> >What could Lucy do that H.erectus couldn't?

With her short legs and long arms . . . .

Let me suggest that one thing at which she would be much
better is foraging for small objects on the ground. The
H. erectus (and H.s.s.) shape is poorly adapted for much
general agricultural work at ground level, such as picking
strawberries. Lucy, with her small size, would be closer to
the ground and if she spent much of her day walking slowly,
leaning forward, gathering small objects, there would be
little selective pressure towards shorter arms, longer legs
and a bipedal stride.

This does not help us much as regards bipedalism itself,
unless we insist that a gathering operation was necessarily
involved, and she was using some kind of natural net or
container. And the big problem remains: What did Lucy do
with her child while she was foraging like this? It's a
problem under any scenario, since (IMO at least) she could
not have been carrying it on her belly. The only general
solution I see is to propose a lot of shared infant-caring
which also probably implies static sites.