Scientists revealed through a recent study that the bones of humans began to weaken as they moved towards modern agricultural practices, UPI reported.
Conducted by American Museum of Natural History curator Brian Richmond and Habiba Chirchir of George Washington University, the study pointed out that the bones of humans evolved to become lighter 12,000 years ago.
The researchers explained that the change in the skeletal structure occurred as humans transitioned from their hunting and gathering techniques to agricultural activities. As they adopted a more sedentary lifestyle, their bones became less dense.
"Despite centuries of research on the human skeleton, this is the first study to show that human skeletons have substantially lower density in joints throughout the skeleton," Richmond said in a statement.
For the study, Richmond and Chirchir compared the joints connecting bones of humans to those of chimpanzees. They discovered that the joints in the lower part of the body such as in the ankles, knees and hips are less dense compared to those of their animal counterparts, according to AMNH.
The researchers explained that when humans became focused on agricultural practices, they stopped roaming to different places and instead stayed in one area. The lack of mobility affected the development of bones and caused them to become lighter.
"Much to our surprise, throughout our deep past, we see that our human ancestors and relatives, who lived in natural settings, had very dense bone," Richmond said. "And even early members of our species, going back 20,000 years or so, had bone that was about as dense as seen in other modern species."
"But this density drastically drops off in more recent times, when we started to use agricultural tools to grow food and settle in one place," he added.
Richmond noted that the findings of the study can be applied to today's medical practices in explaining disorders affecting the bones such as osteoporosis.
"Over the vast majority of human prehistory, our ancestors engaged in far more activity over longer distances than we do today," he said.
"We cannot fully understand human health today without knowing how our bodies evolved to work in the past, so it is important to understand how our skeletons evolved within the context of those high levels of activity," Richmond added.