Now this is where it stops making sense. Why was infant mortality so high if their health was otherwise perfect?

Because when all is said and done babies are very fragile. In our society they have the benefit of an extremely controlled environment where they are barely exposed to the vagaries of mother nature. Then they have full access to advanced medical care, should something go awry. Even in our "soft" society we consider babies fragile and we take utmost care with them.

Our ancestors health was perfect probably in large part due to the fact that they were the ones that survived infancy and the descendants of men and women who survived their infancy. I guess it probably depended a whole lot on your environment, but some of them were pretty harsh. Weakling babies, toddlers or children probably never made it out of childhood. In some of the harshest places, where it was important for all members of the group to be strong, the weak ones were probably not allowed to grow-up, even if they did manage to survive.

Then on top of all that, they lived in a decidedly rough environment filled with physical dangers and predators, and were encouraged to explore fully with a minimum amount of codling. No keeping the kids indoors and parked in front of the TV, because parents are afraid they might cross the street alone.

Including pre-natal care. If mom isn't getting enough food (pregnancy during winters), or she falls, or has to run great distances, the birth weight of the baby will be low and it's at a disadvantage from the start. It probably won't make it if challenged health or nutritionally.

I'm sure there were lots of stillbirths and miscarriages during winter. Just being pregnant in this environment would make a woman vulnerable.

So how do all the other species do it then? Rather, do all other species also have a high infant mortality for any other reason than predators?

If humans were the top of the food chain, they wouldn't have to worry about predators. If humans didn't suffer the DOCs because they didn't eat the SAD, they wouldn't have to worry about anything related to the DOCs that would also affect infants. So no predators, no DOCs, then why the high infant mortality?

I don't get it. Humans have the single most powerful tool to their disposal: Their brain. Look at the wonders we've created with it. The I Caveman show tells us that if cavemen needed one thing more than anything else, it was their brain. Are we suggesting that reproduction was something they left to chance, that they didn't interfere or didn't make sure their offspring would make it by any means they could? But that's absurd. I'm certain that they would have had complete knowledge of reproduction and pregnancy in all its facets.

No, if anything, human infant mortality would have been lower than any other species once we started using our brain.

Put the question differently. Can anybody find any reason why we would not have applied our smarts to reproduction like we did to hunting, gathering, shelter, clothing, and basically all other aspects of our existence, once we developed sufficient brains for it?

Consider the I Caveman show. No butcher, no cattle rancher, no supermarket. Everything that had to be done, they had to do themselves. Now consider reproduction. No medical doctor, no OBGYN, no nurse, etc. Everything that had to be done about reproduction, they would've had to do themselves. They would've had to become experts in everything that had to be done. That was basically the lesson of that show.

Making my mark so I can be updated.. Interesting thread.

This raises the question, where did he learn about the Atlatl? Probably from the internet or some book. Remember the big guy, how he sorta knew about traps and stone tools and whatnots out of nowhere? Well, he probably learned about all that on the internet and books too. Books is how we transmit knowledge today. So how did the caveman transmit his knowledge back then? Well, at the end of the show, they started drawing and carving images of the hunt on trees. That's how the caveman transmitted his knowledge. So the purpose of all those cave drawings wasn't Art, it was teaching.

Think about it. The drawings often include men holding weapons in a throwing stance, then the weapons themselves in detail, then the weapons flying toward the animal being hunted, then the animal with the weapons sticking out of its flank. Just like we'd see today in an instruction booklet if we'd made one about hunting Elk with the mighty Atlatl. Now consider how significant that hunt was to the group. It allowed them to live worry-free for the remainder of the experiment. Imagine the effect of hunting on cavemen, the same thing. It follows that teaching hunting would have been given as great an importance as the effect of that hunt had on life as a whole.

I've just been reading a bit about cave paintings and nobody seems to have any idea what their purpose was. Well, it looks like I just figured it out. Cave paintings are instruction manuals primarily for hunting.

From Human Birth: an evolutionary perspective by Wenda Trevathan:

OK, so birth is difficult because of cranium size vs birth canal diameter. But we can note that the same diet that causes DOCs, also affects skeletal structure, and thus birth canal diameter. So no DOCs, no narrow birth canal. What else?

Wow. Usually, Martin, I'm right on board with you, but that's too fast and sure a leap for me. Narrow birth canal caused by DOCs/modern food? The argument is that bipedalism requires a narrow birth canal; DOCs don't enter into it.

DOCs enter into it when the cranium is affected as seen with the narrow spacing of the eyes, the narrow nostrils to the point of blockage, the crowded teeth, etc. Weston Price stuff. If the DOCs do this, rather if the diet that causes the DOCs does this to the cranium, then why not the pelvis?

Has anybody ever considered this ever? If not, then can I say I'm the first to figure it out, if that's what's really happening, of course? Yet again, Martin to the rescue. Thank you, thank you, where's my limo.

Consider calcification. It's a hardening of tissues. It probably affects the skeleton too. Now consider that the older we get, the more pronounced this calcification simply by virtue of having more time for the calcification to occur. Consider that bone calcification would affect the widening of the pelvis that occurs especially after a first pregnancy (symphysis pubis). Now consider that we make babies later and later which allows calcification to progress further before the first pregnancy. And we get a difficult birth simply by virtue of a narrow pelvis due to too much calcification which prevents otherwise normal full widening of the birth canal.

Now consider that the diet that causes the DOCs also affects normal pelvis growth (remains too narrow) and it's easy to see why birth is generally more difficult today.

It's just quick and dirty hypothesis, but it's good enough for the purpose of discussion.

The idea that bipedalism requires a narrow pelvis (and opposes the need for a wide pelvis for pregnancy) doesn't explain the lack of or insufficient widening of the pelvis for the first pregnancy. I mean, this is controlled by hormones. Does walking affect those hormones?

Martin, your modesty never cease to amaze :P

I remember some Weston price stuff that hunter gatherers had an easier thing given birth. So yeah, I wouldn't be surprised if nutrition can change the size of the pelvis.

Regarding the other comments regarding pre-natal care. They actually had that. Apparently most populations had a sacred food(s) that was given to pregnant and nursing mothers. That food what typically very high in nutrients. I forgot where I read that though. So yeah, they had natal care covered. Of course if the group is starving, then yes, the babies might suffer. But remember that a growing baby is very much like a growing tumour. If the nutrients are insufficient, it take it from the mothers organs, bones and muscle.

So to comment on your comment Martin, I'm sure that men applied their intellect when it came to reproduction. But it's still a chancy thing, and a lot can go wrong. Look how many cesareans are performed. Granted, a lot of those are unnecessary (like so many medical procedures) but the ones that ARE necessary would probably result in the death of the mother and/or the child, had they not been performed. Once you deliver the baby, you can get infections, you can bleed to death, so many things can and do go wrong.

And human babies are much more fragile than other species. They are helpless for a very long time, which multiplies the potential for mishaps. Most other animals are grown and ready to reproduce by the time a baby stops nursing. Herbivores typically can follow their mother within hours of being born. Some prey species are more vulnerable, but they often compensate by having a high reproductive rate.

Also other animals probably have a very high infancy death rate. If a doe, for example, managed to produce one baby per year during her lifespan, and most of those offspring survived, we would be neck deep in deer. Same for predators, who usually produce a litter every year. So it might well be that despite our high infant mortality rate, we do much much better than most species. How else would we have covered the world from pole to pole like a plague of locust. I am reminded of that every night when I use the bus to commute home.

This is interesting. Could that be why our brains have shrunk since the Paleolithic? Childbirth would have become more difficult than it was and the smaller-brained infants would have been selected for.

We are shorter too. This is explained by our diet, particularly grains. Why not our smaller brain too? In spite of the smaller brain though, it's more difficult to give birth now than it used to be if we consider everything such as the effect of diet on the pelvic bone, birth canal diameter, etc.

Our growth is controlled by hormones, and diet can have a very significant effect on our hormones, never forget that.