years ago. He published that
research in 2005. Now, thanks
to analysis set to be published
in the July 2008 issue of the
Journal of Archaeological
Science, Trinkaus has found
that humans were probably
wearing shoes even earlier,
about 40,000 years ago.
Through thick and thin
Trinkaus' theory is based on a
simple fact: Bone size isn't set
in stone.
"Bone, at least to a certain
extent, responds during a
person's lifetime to the
mechanical stresses placed on
it," said Tim Weaver, a
University of California, Davis,
anthropologist. "If you work
out at the gym, not only will
your muscles get bigger, your
bones will become thicker."
For most of their history,
humans had big, thick toe
bones. Trinkaus said this was
because they were doing more
walking, climbing and carrying
than we do today. In fact, he
said, all their leg bones were
bigger as well, for the same
reasons. This is true for both
Neanderthals and the earliest
modern humans.
But, around 40,000 years ago,
that began to change. Trinkaus
noticed that skeletons from this
time period still had strong,
thick leg bones, but their toes
had suddenly gotten smaller.
"They had wimpy toes," he
said. "I tried to figure out what
would take away stresses on
the toes, but not the legs, and
the answer was shoes."
First shoes, first tailors
While Weaver agrees with
Trinkaus' theory, Cachel
doesn't buy it. She pointed out
that, not long after the time
period Trinkaus looked at,
humans apparently stopped
being so active and all their
limb bones, not just the toes,
started to shrink.
"If the footbones are smaller,
this probably reflects less
walking and physical activity,
rather than the invention of
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