What is the evolutionary reason we live, on average, 40 years longer than our reproductive ability?

[justanotherneighinparadise]

I was pondering this whilst putting in my make up 🤣

If the sole reason for existence is to reproduce, why do we generally live forty years or so later than our eggs viability?

The only thing I’ve come up with is to be old enough to raise our own children to adulthood and then perhaps be the matriarch of a troop and help raise grandchildren etc?

@FindHungrySamurai

I suspect that it’s related to the sheer uselessness of human infants, which as a pp said is probably linked to our upright stance which means that human reproduction is a godawful bodge job compromising on the size of head you can get through our pelvises without quite killing either mother or baby. Trust me, I have the scars to prove it.

As a mother of twins, the thought of carrying them both long enough to walk their way out of my womb virtually is terrifying.

@jeannie46

Large numbers of my ancestors/relatives, died in infancy/young (under 25) in the 17th, 18th, 19th , 20th centuries ( of various ghastly diseases - TB, diphtheria, heart problems , accidents at work etc.) One poor chap in 18th Century had 16 of his 18 children die in infancy. Both wives dead by 40. Several women died in childbirth. In these circumstances the children were raised variously by aunts, grandmothers/fathers (even sometimes helped by their great grand parents!) I have a female ancestor born 1830 died 1927, male one born 1860 died 1957 - both helped with child care. These long lived ancestors were crucial in the survival of their descendants. Women and men working long hours hunter/gathering, on the land or at cottage industries ( well before the arrival of the factory system) needed some one to care for toddlers, the sick , injured etc etc.

Oh goodness how sad that all was. The heart ache of the past really makes me well up. Didn’t one of the queens miscarry something like 12 pregnancies? I remember watching the documentary and just crying for her.

We hang on to our kids the most out of any mammals, maybe that’s something to do with it?

I don’t believe it’s for childcare as other mammals do childcare too, like lionesses but only for a little time. I can’t believe we are given a extra 20 years to raise grandchildren.

It’s only around 40 now due to medicine

@Heartlantern2

We hang on to our kids the most out of any mammals, maybe that’s something to do with it?

I don’t believe it’s for childcare as other mammals do childcare too, like lionesses but only for a little time. I can’t believe we are given a extra 20 years to raise grandchildren.

It’s only around 40 now due to medicine

Yes but lion cubd are infinitely less useless than human babies. Mine are 1, they can't even walk, barely feed themselves adequately and have a mere 6 teeth each which wouldn't cut through much. They'll be a decade off from anything near proper sufficiency and ideally more. 10 year old lions are not weaklings with under developed brains who still need some level of monitoring

I did write ‘medieval times’ and ‘Hunter gatherers’ in different paragraphs! Did someone think I thought these were the same era?!

I understood what you meant, Sarah.

Humans may have a somewhat unusual combination of offspring who are juvenile and pretty much helpless for years plus risky birthing without medical intervention. Without family members to raise youngsters, a maternal death would result not only in the inevitable death of the newborn but probably also many of its older siblings.

In primitive times women would start having babies in their late teens, would breastfeed each baby for 2+ years and would have a baby approximately every 3 years, as in a lower nutrition environment, breastfeeding will act as a contraceptive more effectively than it does in modern times.

So a 45 year old woman will probably be on her last baby, which she will breastfeed for another couple of years. She may also have 3 other children under the age of 10. She needs to live at least another 10-15 years to give those last 4 children a reasonable chance of living to have children of their own. If she carries on childbearing until she dies of old age her last few children will have no chance and the toll on her body will probably result in her dying younger than if she had gone through the menopause.

It is more efficient for a woman to concentrate resources on existing children and grandchildren past a certain age. She will have more descendants if she does this than a woman who is fertile past 50. In this way evolution has caused selection for menopause.

Men do not have a toll on their body through childbirth and nursing, and in primitive societies they do much less childcare so it isn't advantageous to them or their descendants to stop having children with age, as long as they can attract a woman young enough to bear them.

Didn’t one of the queens miscarry something like 12 pregnancies

Queen Anne had 17 children I think and none reached adulthood.

@cologne4711

Didn’t one of the queens miscarry something like 12 pregnancies

Queen Anne had 17 children I think and none reached adulthood.

The only child who survived birth died at 11 😔

✌️ Fold, one to help raise gc but also to help drive families far apart so they don't mix genes... Ie even in tribal days I bet people escaped difficult mils.

Also menopause, leaving the poor woman hairy, angry and looking older, wrinkled breasts, dry vaginas would also push a fertile male to go and form his next family, with a younger mate.