JOY FEELINGS MAGAZINE December 2015 | Page 294

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 JOY FEELINGS | DECEMBER ISSUE 294