The change from a very demanding life of hunting, psychically speaking at least, to one of agricultural labors could explain why modern humans have thinner bones compared to other primates. Our bones are thinner, lighter and more fragile than they were thousands of years ago.
Scientists have reached this conclusion after they compared hip joints from foraging people and early humans who discovered agriculture and switched from hunting. The team of researchers compared their bones to nonhuman primates.
Timothy M. Ryan, one of the researchers involved in the study about human bones said that his team had three theories about the reasons behind human bones thinning over time. He said that one of the most plausible theories was that the bones have thinned because the lack of constant physical activity, which causes bones like the femur to become thinner and lighter.
The researchers compared these bones to the ones of modern primates like orangutans, gorillas and chimpanzee, primates that are more mobile populations.
The other theories that could explain why human bones changed refer to the fact that humans and nonhuman primates have a different bone structure that is strictly genetics. Humans have naturally evolved to a lighter structure unlike nonhuman primates.
The human bones analyzed by the scientists are hip bones that belonged to two agricultural groups and two foraging groups. The bones were discovered somewhere in Illinois, while the non human bones came from wild specimens from different collections.
The researchers analyzed the bones using noninvasive tomography in order to scan the hip joint ends of the femurs. The researchers analyzed a total of 59 adult humans and 229 nonhuman primates.
Colin and Ryan N. Shaw from the University of Cambridge compared the trabecular bones among the three groups. They discovered that the human populations with divergent activity patterns have different trabecular bone structures that other groups.
The researchers discovered that the humans who did agriculture had significantly lower bone mass than the humans who did foraging. The researchers also found that the bone structure of the foraging humans who were more mobile was more similar with the bone structure of nonhuman primates.
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