How come labour last such a long time, and is essentially a dangerous procedure? Both my Mum and my sister have had complications during childbirth (it was OK though).
Other mammals don’t seem to have the same problems that humans do. They don’t need any assistance or drugs, and generally just get on with it. What would be our mortality rate if we didn’t have medical science?
It seems like a design fault in humans, but you would have thought that this is the sort of problem that evolution would sort out in relatively few generations.
Hmmm. How many mammalian births have you witnessed? Who collects infant mortality statistics on wild animals? I would challenge your assumption that other mammals don’t have the same problems we do. They don’t get assistance or drugs, but that doesn’t mean they are spectacularly successful without them.
Evolution is not a problem-solving process or a design process. It is not a goal-oriented process with some coherent driver. It is simply a description of the tendency for animals that have characteristics making them fit to reproduce to actually reproduce, and for those characteristics which can be inherited to also allow their offspring to reproduce, and so on.
Some things that cause difficult childbirth might be inherited, but some not.
In less civilized times (even in earlier civilized times when there more frequent deaths in childhood), I would posit that women had more babies than they do today, and therefore a greater chance that at least some would survive to reproduce. More women probably died in childbirth, too, but as I suggested, that may not be genetic and therefore would not necessarily result in the gene pool producing women more able to tolerate childbirth.
I’ve thought about this too. My theory is that the increase of our brain size has been relatively rapid, in evolutionary terms. Absent modern medicine, female physiology would probably still be in the process of catching up.
As to the “animals not having trouble” assumption, I’d just like to add…
I’ve been “mother” to at least a dozen kitten litters in my lifetime, and only 2 resulted in a litter with no losses. The average seemed to be about one kitten lost per litter.
And as to your “evolution should sort it out” theory, that would only be feasible if medicine did nothing to aid a difficult delivery. The very fact that we are able to overcome the diffuculties posed by women delivering baby’s with such large heads means it’s not something that should be fading out of practice anytime soon.
The two issues of fetal death verses maternal death during childbirth are being somewhat conflated here. Yes, you will lose the occasional kitten or puppy. But generally, childbirth is relatively safer for the mother in most species than it is in humans.
Maternal death in large mammals is most commonly associated with unusually large fetuses. Almost all human fetuses are, relatively speaking, unusually large. And, as has been noted above, this is indeed a relatively recent development, evolutionarily speaking.
Yup. As a male, we are in an ideal situation, women’s evolution-wise. Big, healthy offspring, yet vagina and pelvis sizes have yet to enlarge to accomodate birthing these big babies more easily.
I also remember reading somewhere that humans are reversed from basically all other primates in how the baby comes out. If I remember correctly, because a human child is born face down, people like midwives are a necessity, while in basically all other primates, the baby is born face up, so the mother can more easily reach down to help the baby out and pull it up to the breast. However, I don’t believe this was as much of a biology article as it was a sociology article.
Alas, I can nutshell it (as I just did) but can’t elaborate. I’m not a biological anthropologist and that’s as much as I can remember of the basic explanation. Human heads got bigger; pelvises changed to support an upright body; these two changes ain’t exactly compatible.
CrankyAsAnOldMan, for some reason I thought that you might have a viewpoint on how this could be different. :smack: Perhaps I need to sleep more. It would be interesting to hear someone’s views on how evolution could have been or be more efficient, though. Off to GD!
I’m wondering what the alternative would be… hunchbacks with necks craned back? Have you noticed lately that more people hunch than before (5 years ago). Thank goodness for the internet, computers, and these damned uncomfortable chairs. Excellent lumbar support my ass…
Except that female physiology will not catch up, as CookingWithGas accurately points out:
Though human females may not have relatively effortless and painless births, they are in fact fit to reproduce. A minimum level of reproductive fitness is all nature requires. Pass on the genes – evolution doesn’t care how you do it … just pass 'em on.
This is quite correct. Humans do have much more problems with childbirth in terms of difficulty and potential death of the mother than almost all other mammals - including the great apes. And this is not so much because of the large size of the baby, but because the head of a human infant is so extremely hypertrophied compared to the size of the body. A human female’s pelvis is also greatly expanded compared to that of a chimp, to the extent that a typical female can’t run as efficiently as a male. (Notice that in a chimp, it’s rather difficult to distinguish a male from a female just on the basis of hip size, where this is pretty obvious in average humans.)
Human infants also are born in a relatively undeveloped state compared to those of apes. A young chimp is capable of walking, etc, much sooner than a human baby. So all humans are essentially born quite prematurely considering their developmental state. In one of Stephen J. Gould’s books, Ontogeny and Phylogeny, IIRC he states that if humans were born at a comparable state of development to apes, pregnancy would last something like two years. Obviously, if that were the case, humans would have far worse problems with childbirth than they do now.
There are trade-offs between infant brain size and developmental state at birth, vs. female pelvis size (too wide, and you can’t walk well; too small, and you die in childbirth). Human evolution has pushed infant brain size close to the limits imposed by female anatomy.
The theory that the difficulty of delivery is related to recent, rapid evolutionary changes makes a lot of intuitive sense to me. There are other mammals that have some difficulty with birth – such as domesticated dogs, cattle, sheep, and horses – which sometimes require human intervention (“Call the vet, Midge! I think it’s a breech!”). But these are all domesticated species, whose variegated breeds have been rapidly multiplying and evolving through animal husbandry.
Humans are the most domesticated species on earth. They can’t do much of ANYTHING on their own.
But seriously, although humans have pretty much maxed out the compromise between walking upright and brain size on a physiological level (QED), we have over come that obstacle with that lovely innovation called the C-section (of which FAR too many are currently performed…but that’s a whole 'nother Oprah). Now we can enjoy the evolution of mammoth brains…meaning BIG, not furry elephant brains, that would be silly…while retaining the pleasantness of small female pelvises. Ain’t science grand?
But seriously, please elaborate. I am ready to receive your knowledge.