Biomedical Engineering Reference
In-Depth Information
sharpened ovate form allows the projectile to transfer more of its
momentum into the animal, causing a more pronounced (and deadly)
flexion response. Four or five hunters simultaneously throwing hand axes
could multiply the efficiency of the technique.
Calvin's theory would help explain many of the enigmatic aspects of
the hand-ax shape: the sharpened edge all around (which makes it hard
to use as a handheld ax), the persistence of the ovate shape (which he
says is difficult to explain in other than aerodynamic terms), and the fact
that many hand axes appear “unused,” lacking edge wear. It would also
explain why some Paleolithic sites have literally thousands of such
objects, since it is not hard to imagine hunters losing half a dozen on
any given day at an oft-visited water hole, especially when the water was
high.
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The theory also has the advantage of not requiring cultural trans-
mission to explain the constancy and ubiquity of the hand ax's shape:
its persistence could simply be a consequence of its effectiveness as a
hunting tool. Hominids throughout the world might have experimented
with throwing rocks at animals where they gather and have found that
rocks shaped in certain ways work better than others. The Acheulean
hand ax might have been independently invented thousands or even
millions of times in different parts of the world; stones from previous
hunters might also have been perennially rediscovered, as water holes
dried up or erosion caused their reexposure. Hand axes in this sense
may have been a constant part of the geo-ecology of the hunting
environment.
A rather different approach has been to claim that Acheulean tools are
not in fact so uniform as they might at first appear. There are different
shapes and sizes (some as large as thirty centimeters in length).
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And
there are, of course, different kinds of materials, the earliest African
assemblages being more often basalt or quartzite, while subsequent
European tools are more often flint, chert, or jasper. There are Acheulean
sites without hand axes (Clacton-on-Sea in England), and Acheulean-like
hand axes that persist into the Late Mousterian that were probably used
by Neanderthals (these tend to be classed as “Clactonian” rather than
Acheulean, and were made from smaller flakes). The selection of appro-
priate materials may have involved a great deal of skill and connois-
seurship lost to us today; the fact that, to most of us, Acheulean tools
“all look alike” may be partly an artifact of distance and lack of
