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It's common that human females have a more flexible body than males, (but I don't know why, so it'd be helpful if someone answers why so as well!) but does this apply to all mammals?

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In which terms more flexible? – Chris Mar 24 '14 at 13:13
You mean physically flexible ? – biogirl Mar 26 '14 at 4:26
Do you mean plasticity? Devlopmental plasticity? – Remi.b Mar 26 '14 at 9:49
up vote 1 down vote accepted

Try birthing a child for once. You need to be flexible to accommodate the growth of another organism inside you.

Take a look at some pictures of the mothers spine during the course of a pregnancy, you will have no further questions. Same with belly size, breast size and vagina size upon birth.

This video is a nice explanation of this. Also includes the different centers of gravity for males and females (human).

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This might be true for spinal flexibility, I'm not sure it tells the whole story. Men are almost always stronger than women of the same size, and I'd be surprised if this isn't related to flexibility. Perhaps women pay for their increased flexibility with reduced strength? – atrichornis Mar 26 '14 at 10:21
Males and females are more similar in most other mammals (with some spectacular exceptions where males compete strongly for females and have evolved weaponry to help them). When your life is threatened every day and you survive by running and fighting, there is a strong evolutionary incentive for both sexes to converge on a single optimal body shape. – atrichornis Mar 26 '14 at 10:24
@DisplayName yes, I find that the spine curve gets very intense during pregnancy. – Greek Fellows Mar 29 '14 at 3:41

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