The female pelvis is subject to more variations than that of men. From puberty, it undergoes an increased development, modifications objectified by imagery.
Why do women have more generous hips than men? It would be an evolutionary trick. It allows expecting mothers to develop a pelvis that is more conducive to the delivery of a full-sized baby. This is explained by a study published in the journal of the American Academy of Sciences, PNAS. Men, who do not need such abilities, maintain narrower hips which are better suited to bipedal walking.
A peak at 25
Until now, the scientific community believed that the human pelvis was a compromise between the need to walk on two legs and the need to give birth for women. Wider hips would hinder walking, even if it means causing more painful childbirth. But this hypothesis seems false, in view of the elements put forward by the team from the University of Zurich (Switzerland).
The authors have indeed followed the development of 275 female and male pelvis, from birth to old age. Until puberty, growth, and dimensions are similar in both sexes. It is only from adolescence that a dropout occurs for young women. While the progression curve of the male pelvis remains constant, that of the female pelvis is experiencing a great progression. The peak is reached around 25-30.
End of variations at age 40
This difference in pelvic growth is explained, according to the researchers, by different hormone levels. At puberty and until menopause, estrogen is highly concentrated in women. This helps ensure the development of the pelvis is consistent with fertility. A great find from an evolutionary point of view. “This means that the female body can modulate its pelvic dimensions ‘on demand’ and that it does not depend on developmental programs frozen on the genetic level”, underlines Marcia Ponce de León, who signs this work.
From the age of 40, the effect of hormones wears off and the pelvis begins to shrink. It then joins dimensions closer to those of men. In fact, a narrower pelvis is better suited to walking because it stabilizes the pelvic floor, allowing the pressures generated by walking on the abdomen to be absorbed. Researchers also do not rule out the effects of walking. environment and nutrition on these anatomical variations.
Source : MorphoLab, Anthropological Institute and Museum, University of Zurich
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