all of that, yes, but I generally see a 15-25 range in estimates, I’ve never seen one that low.
“Cite?”, I guess is what I’m saying…
The estimates of lifespans from earliest times to about 1900 usually fall in the range of 20 to 40:
No, estimates of lifespans from earliest times to now are all in the 70ish range. Lifespan is not the same thing as life expectancy.
Also the woman were having babies at a young age. How young not sure but certainly back then by 15 or 16, if not earlier.
True; but it also seems likely that they breastfed their babies for a long period (up to three years or more), which would have suppressed ovulation and prevented a new pregnancy.
As the younger member of a pair of Irish Twins in my class pointed out during Sex Ed: “baloney!” IOW, if that had actually been a good method to avoid getting pregnant, she wouldn’t have been born (neither would my mother’s younger sister, for that matter).
Well, it’s not infallible. But neither are birth control pills.
I have a hard time believing that for two reasons.
1st growing up I knew a lot of families with two kids no more than 11-14 months apart. This includes mine as my 2 older brothers are only 12 months plus a few days apart in age.
2nd is from an evolutionary point of view. Since there was a high degree of early childhood demise back then I suspect the evolutionary thing to do would be to have lots of babies.
I’ve seen that number quoted a lot. Here’s one:
and
On the first point: as I already said, it’s a matter of statistical probability, and you’ll certainly find some outliers.
(It probably also matters whether the babies were dependent on breast milk as their only food source or had some additional formula.)
On the second point, I believe it does make evolutionary sense. If a woman is breastfeeding a child, a new pregnancy, childbirth and the need to nurse an additional child might well reduce the overall chances for any of the offspring to survive.
If you have four kids, and three die in childhood but the fourth survives to their 30s or 40s that gives a life expectancy of about 10.
I thought life expectancy for pre agricultural societies was 15-25,id never heard of it as low as ten.
What kind of data do we get from today’s hunter-gatherers or those who were hunter-gatherers in recent enough times to be studied?
In non-hunter-gatherer groups like ancient Rome, food shortages wouldn’t have been as much of a problem. So in what situations would they practice infanticide?
I got an IUD right on the day when I was able to start sex again. Lucky because I soon got my period, though I nursed for 35 months
Any cites?
Ignotus:
Heh. I can personally attest to both of those.
It seems nonetheless to be the case. Cite.
Humans have an unusally long period of infancy and helplessness. Therefore the strategy of having many offspring and relying on a small minority of them surviving to reproduce doesn’t work as well. The ‘strategy’ that has evolved, therefore, is to have fewer offspring, invest more in each one, and ‘hope’ that enough survive.
Regards,
Shodan
I wonder if this has anything to do with food availability. In the same manner that girls start puberty earlier if they are well-fed. The article doesn’t say.
I don’t know why people are bringing up “historical records” when the OP specified 50K years ago. The only hard data that archeologists have is the age of fossil skeletons found, and what they tell us about average age at death, supplemented with some minimal data we might have about “modern h/gs” (keeping in mind that there are no such groups around today that qualify for that category in the sense that our 50K years ago ancestors did). Fossil skeletons being such rare occurrences, one can expect our estimates of LE to come with rather large error bars.
But if we really want to talk about those historical records cited during medieval times, some of that is going to be skewed, if you will, by periodic episodes of plague that ravaged Europe. I put “skewed” is quotes only because those were natural events and shouldn’t be ignored altogether-- but it also might be informative to looks at LE for plague and non-plague periods.
Nursing is most effective at stopping ovulation when you are nursing a lot–if you are supplementing with formula, or if the baby is also eating solid food (and so nursing less), it becomes less effective.
Do you really know how often your mom , or your friends’ moms nursed, and whether or not they used formula for night feedings, or when they switched to solid food? Depending on your age, it’s really very possible they didn’t nurse at all, and even if they did, doctors used to recommend starting at least a little solid food very early, like six weeks.
Chronos writes:
> No, estimates of lifespans from earliest times to now are all in the 70ish range.
> Lifespan is not the same thing as life expectancy.
Yes, I should have written “life expectancy.” In any case, the estimates generally given for average life expectancy from prehistoric times to about 1900 are all in the range of 20 to 40 years. The book that CJfromSanAndreas is quoting from is thus considerably different in saying that it was 10 years. Please, CJfromSanAndreas, tell us what book you’re quoting from so we can check it and compare it with other sources.
The life expectancy for oysters is pretty close to zero, since maybe one in a million fertilized eggs makes it to reproductive age (although if they do so they can survive for a long time). Yet somehow they manage to be abundant in places.