Women evolved to have bigger hips than men because our primitive ancestors laid EGGS, study claims

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Women evolved to have bigger hips than men because our primitive ancestors laid EGGS millions of years ago, research claims.

  • For years it was thought that women have wide hips to give birth to babies
  • But female chimpanzees also have wide hips, despite having smaller babies
  • Experts say a shared ancestor developed wide hips to make egg laying easier

Women evolved to have wider hips than men because our primitive ancestors used to lay eggs, new research claims.

For years, it was thought that the reason women have wider pelvises is that human females have ‘weight-bearing hips’ to allow the passage of large-brain babies.

Human babies’ heads are the widest part of their bodies, and the pelvis must be wider in women to accommodate this.

But the new findings – which will give new meaning to the phrase ‘being broody’ – say that wide female hips go back much further than that.

Women evolved to have wider hips than men because our primitive ancestors used to lay eggs, new research claims (stock image)

Women evolved to have wider hips than men because our primitive ancestors used to lay eggs, new research claims (stock image)

WIDE HIPS

Chimpanzees, our closest ape ancestors, have enviable trouble-free labor and pelvises that don’t impede the birth of babies, but females still have wider hips than males, suggesting that large hips started many years earlier.

Analysis of reptiles also shows that females also have relatively wider hips – and this may be key.

Wider beaks in females make it easier to lay eggs.

The researchers suggest that wide hips is a trait with a long evolutionary history, and that the broader pelvis in females “ already existed in early mammals, ” adding that its purpose may have been “ to lay large eggs in proportion to body size. adults’.

Barbara Fischer and colleagues from the University of Vienna explain their research in Nature Ecology and Evolution.

No bone in the human body is as different in size between men and women as the human pelvis – and as such, it is the most reliable way to distinguish between the sexes, the authors write.

But the reason females have a wider pelvis must have a different explanation than childbirth, because even in creatures with small babies, such as the Virginia opossum, which gives birth to only one-thousandth the size of the mother’s offspring, females also have wider hips. . .

Further evidence that large hips have an ancient evolutionary history comes from the study of chimpanzees.

Chimpanzees, our closest ape ancestors, have enviable trouble-free labor and pelvises that don’t impede the birth of babies, but females still have wider hips than males, suggesting that large hips started many years earlier.

Analysis of reptiles also shows that females also have relatively wider hips – and this may be key.

Wider beaks in females make it easier to lay eggs.

The researchers suggest that wide hips is a trait with a long evolutionary history, and that the broader pelvis in females “ already existed in early mammals, ” adding that its purpose may have been “ to lay large eggs in proportion to body size. adults’.

Dr. Fischer told the Daily Mail, “The female pelvis may indeed be wider because an evolutionary ancestor of ours laid large eggs.

In our article we show the evolutionary pattern of a sexually dimorphic pelvis [differing between the sexes] was not developed by modern humans but is inherited from our ancestors and may indeed have evolved from early mammals or amniotes [other animals such as birds and reptiles], who laid large eggs or gave birth to large fetuses. ‘

In the study, the researchers measured the female's mean pelvic shape (top row) and the female chimpanzee's mean pelvic shape (bottom row) in anterior (left-most), superior (middle), and lateral (right-most) views.

In the study, the researchers measured the female's mean pelvic shape (top row) and the female chimpanzee's mean pelvic shape (bottom row) in anterior (left-most), superior (middle), and lateral (right-most) views.

In the study, the researchers measured the female’s mean pelvic shape (top row) and the female chimpanzee’s mean pelvic shape (bottom row) in anterior (left-most), superior (middle), and lateral (right-most) views.

It’s just as well that humans kept genes that enabled wide hips, because when our brains began expanding rapidly in our ancient ape-like ancestors 2.5 million years ago, the genetic ‘machinery’ was already in place to make the hips expand. , the researchers said.

The researchers write that “the genetic and developmental mechanisms to develop a wider female pelvis were already in place, they did not need to evolve again.”

Of the mammals that exist today, only platypus and thorny anteaters, also known as echidnas, lay eggs.

Women with wide hips have more sexual partners and are ‘more likely to have one night stands’

A study in 2014 has shown this women with wide hips are more likely to have one night stands and more sexual partners in general.

Essentially, this is because they do indeed find childbirth less traumatic, the authors suggest.

The researchers define wide hips as those wider than 14.2 inches (36 centimeters) and small hips as those smaller than 12.2 inches (31 centimeters wide).

This is measured by the distance between the top outer edges of the pelvic bones of the pelvis – the widest part of the hip bone.

The measurement is about the circumference, not the circumference.

Of the 148 women in the study – aged between 18 and 26 – their hip circumference was also measured at the widest point and their waist circumference at the narrowest point.

All women previously had at least one sexual partner. They also completed a questionnaire about their sexual history, including the age at which they lost their virginity, the number of sexual partners they’d had, and information about emotionally significant sexual relationships they’d had.

The researchers, from the University of Leeds, found that women who were more prone to one-night stands had wider hips.

More specifically, the women for whom one-night stands accounted for three out of four of their sexual relationships had hips that were at least 2 cm wider than those who had fewer one-night stands.

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