Paleo Lifespan

In my post about sunshine, my friend Matt brought up that since Paleo humans only lived to be around 30 years of age, perhaps they didn't live long enough to be affected by things like skin cancer. The 30 year life span is something I recall learning in school, so it's obviously something that is pretty well excepted in the scientific community. But, in the reading I've done about Paleo humans I remembered coming across a few challenges to that assertion. Here's one such challenge... written by a doctor, not some asshole with stupid blog :P

http://paleodiet.com/life-expectancy.htm
This is really worth the read.

One solid point made is that in order for us to increase numbers, a mother would have to have upwards of 2 children. And since a breast feeding mother be

unlikely to conceive due to prolactin production, which is stimulated by an infant suckling its mother’s nipples. Prolactin decreases normal levels of the sex hormone, estrogen. This inhibition of estrogen is responsible for loss of the menstrual cycle and consequent losses in fertility among lactating women. We can only guess at how long mothers would breast feed, but it does seem likely that they would have been aware of breast feeding’s protective effect against pregnancy. Assuming that they continued to breastfeed their children to more than two years of age, and allowing another nine months for the second pregnancy, children should be spaced at least about three years apart.

So, how old would a mother have to live in order to foster 2+ children assuming she began procreating at puberty?

A first child would be likely to enjoy its mother’s nurturing until puberty. Mom would be 26 to 29 years old by then. The next child would have a mother who was 29 to 32 years old. But that would mean that she had probably died before the second child reached puberty. If such suggestions of Paleolithic life spans were accurate, we should have numbers and be geographically restricted in ways that approximate other primate populations. Something is obviously wrong with such assumptions about the life span of Paleo Humans. The most likely alternative is that our Paleo ancestors lived longer than is currently suggested.

Again, if you're at all interested in this, and you should be, read this! Now, if you'll excuse me, I'm going further down rabbit hole.