Shoes do a lot more than simply protect our feet, but most of the time we don't realize the physical changes they inflict. For example, wearing shoes can change the way a human walks and how the weight of the body is being distributed on the feet. In modern humans, who basically can't live without shoes, the physical changes can go as far as to affect the bones and the ligaments. Anthropologists are now using the effects wearing shoes has on the human body to understand when they first became popular on the large scale.

There are several differences, noted by Susan Cachel from the Rutgers University, between the feet of people constantly wearing shoes as compared to those who don't. One of these differences is the fact that wearing shoes can lead to bunions, protuberances of the bone and tissue in the big toe. Additionally, people who don't wear shoes tend to have wider feed, and bigger distances between fingers, while women wearing heals suffer a decrease in the mass of the calf muscles.

Erik Trinkaus from the Washington University says that ever since people started wearing shoes their toe bones began to shrink. The oldest pair of shoes ever discovered is dated 10,000 years ago, although the investigations carried out by Trinkaus revealed nearly three years ago that people were wearing shoes as early as 30,000 years ago. A new study now proves that people may have been wearing shoes 10,000 years earlier.

"Bone, at least to a certain extent, responds during a person's lifetime to the mechanical stresses placed on it. If you work out at the gym, not only will your muscles get bigger, your bones will become thicker.", said Tim Weaver, a anthropologist at University of California.

This is especially visible in humans preceding the appearance of shoes who had thicker toe bones and bigger feet since they were doing most of the walking barefoot. Both Neanderthals and the first modern humans also had bigger bones. However, Trinkaus showed that this began to change some 40,000 years ago, when humans started experiencing changes in the toes.

"They had wimpy toes. I tried to figure out what would take away stresses on the toes, but not the legs, and the answer was shoes", said Trinkaus. Cachel on the other hand believes that Trinkaus' theory is incorrect, because it wasn't only the toes that started shrinking but fingers as well, probably due to the fact that they stopped being so active.

"If the foot bones are smaller, this probably reflects less walking and physical activity, rather than the invention of supportive footwear", Cachel said.

Alternatively, the changes in the size of the toes could be caused by a diversity boom of the human culture, as the labor divisions started to appear and the time allocated for decorative clothing increased. "The archaeological record shows many changes, including the types of tools people were making and the first definite artwork, and the oldest needles for making clothing appear shortly afterward", Weaver said.