Fact is people died long before anyone reached the age of menopause. And there are many other more plausible explanations for the increase in lifespan…i.e. agriculture, tool making, group cooperation, brain development that allows you to transmit complex knowledge to you and MOST importantly the advent of language which allows you to convey complex information like tool making and hunting strategies.

Another feel good story, but the fact is females in other species are able to provide the same ‘biological services’ without the advent of menopause….elephants come to mind.

From what I have read it seems to relate more to brain size. Human babies have to be born at such a helpless stage in their development because their massive brain size. They would not survive childbirth if their gestational development went on much further. The human pelvic structure has not even fully caught up with our incredible evolutionary advance in brain development, which is why of all animals only humans optimally require assisted childbirth. Our great big brains are the evolutionary payoff to the cost of being born so physically dependent.

One particular aspect I fail to understand. Let us assume that the human species had two genetic mutations which evolved over the years
1) Human babies aren’t able to feed and take care of themselves immediately after weaning.
2) Female menopause (leading upto the concept of importance of Grandmothers, as specified in this article).

Now, evolution would support #2 primarily based on the facts that #1 already exists within the population. That is, female menopause had no reason to spred amongst the species, had the human babies were more capable of taking care of themselves much earlier like the babies of other primates.

However, it is not really clear, why #1 would spread amongst the population !! What kind of evolutionary pressure would support more and more dependant babies.

Any ideas/ facts on this topic?

Isn’t it also possible though that the evolution of the lengthening of child bearing years just hasn’t caught up yet with the extension of human lifespan rather than the other way around?

There’a a primary assumption stated that human lifespans are actually more than 45 years of age. They aren’t. The archaeological record shows quite clearly that the vast majority of humans only lived between 35 and 45 years of age. Of course there are exceptions, but in 1900 the average lifespane in the US was 47. The reason we now live well into our 70s and 80s is primarily due to modern medicine and nutrition.

Additionally in early societys, as shown in any number of cultural anthrology studies over the last 100 years of tribal peoples, weaning of an infant typcially happens between ages 3 and 4, most often the later. At 4, a child can take care of itself to some degree. With higher primates like chimps and gorillas, there is a similar weaning age and these offspring still have a dependancy on the mother until several years later. There is strong indicators that siblings and older lineal females will tend the younger offspring/siblings. It’s most certainly not as cut and dries as present, with apes abandoning offspring once they are weaned.

I’ve never seen or heard of a study of apes in captivity — zoo or laboratory environments where nutrition and health care can extend their livespans — looking at the possibility of them also reaching menopause. In past human cultures, if probably very save to say very, very few women manages to reach it either.