Tuesday, April 19, 2011

Breastfeeding, Part IV

Before I wrap up this series with my final post about the stuff you can get and do to have a smoother breastfeeding experience, I want to address Megan's question about the role of the father.  It's an interesting question!

First I want to point out something about natural selection.  You've probably all heard Darwin's theory reduced to the maxim "survival of the fittest."  Well, that is true, to some extent, but it's only part of the story.  If natural selection was all about survival of the fittest, then how on earth do you explain a peacock's tail feathers?

That extravagant display of beautiful feathers certainly doesn't help him run faster.  To the contrary, it probably slows him down!  It definitely doesn't help him be less conspicuous to predators.  How could you hide that costume?!  It doesn't help him find food.  In fact, at first glance, it would seem the peacock's tail feathers make him LESS fit to survive!  So why would evolution select for such a seemingly maladaptive trait?  Well, the answer is obvious if you look at the picture above: to attract a lovely peahen mate!

Female peacocks over the millennia selected to mate with the males that had the biggest, um... tails.  They liked the guys with the prettiest display.  Who knows for sure why peahen tastes lean the way they do, but we can infer they like the guy with the grandest, prettiest display because it signals his fitness.  Any guy who has to carry around that huge decoration has to be strong, fast and cunning enough to evade predators, as well as healthy enough to grow the tail in the first place and keep it looking nice.  Females mate with the pretty-tailed guy and his genes get into the next generation.  Meanwhile, those whose tails don't measure up don't get as many chances at reproduction and their genes dwindle.

[This is less to the point, but as you can see, the female is less spectacularly adorned.  That's because she doesn't need to look nice to attract a male.  The males take it wherever they can get it (so to speak).  Because in many species sperm is infinite and males don't have to spend time gestating, they maximize their reproduction by sowing their seed far and wide.  Females on the other hand have to be choosy.  They can only get pregnant by one guy at a time and then they have to invest in their unborn and even young offspring.  So obviously they want only the best.  The males use their tails to prove they are the best and get the females to choose them as a mate.] 

So it's not really "survival of the fittest."  It's more like "survival of those best able to reproduce viable offspring (who themselves are also successful breeders)."  You see, natural selection is the propagation of genes into the next generation, and the next, and the next.  All species have different nuances to their mating strategies; this is only one example.  And of course, not all traits are selected ONLY because they make for an attractive mate... although at the end of the day, that's what much of it boils down to because you can't reproduce or have your offspring be successful at reproducing if you are starving, ill or dead!

Ok, so what about humans?  If sperm is infinite and males maximize their reproductive strategy by sowing their seed as often as possible, why do humans form pair-bonds that endure for many years of reproducing, or lifetimes?  First, because human females selected guys who stuck around.  And secondly because human males probably figured out it was a better way to have viable offspring.  Remember you not only need to reproduce, but ideally see your offspring reproduce in order to see your genes succeed.  You'll also recall that due to bipedalism and our huge brains, human infants are essentially born premature - completely helpless - and require a significant investment from a caregiver in order to survive.  (If only we were like cows and our babies came out and started toddling after us as we went about our business!)  So mom's wrapped up in gestating and nursing for at least a few years: both very energy intensive and not at all conducive to running down dinner.  She needs a mate who will bring home the bacon, as they say.  So the choosy female picks a male she knows has resources to care for her and her offspring.  Over many generations of selectively mating with the guys who want to share and take care, we get human male-female pair-bonds.  Basically what I'm saying is that the males of our species ARE biologically inclined to be very involved with their mate and their offspring.

[Notice I didn't say we are monogamous, though.  I mean, we are, to a large extent, but that is mostly a cultural construct for our species.  Biologically speaking, humans are a mildly polygamous species, which actually benefits females more.  Are you surprised?  Well, think about it: in polygamy, two or three women can share a very fit and "wealthy" (possessing of resources like food, shelter, or able to acquire them easily) male with plenty of resources to go around; under monogamy, each person gets one mate, which insures that all the males can get a mate (good for them and also explaining why adulterous wives are historically severely punished), but that some females will get stuck with less desirable mates.  In this discussion, I'm leaving aside our modern cultural persuasions like romance and commitment.  This is thinking only in terms of reproductive success, i.e., getting the best sperm/resources!  Remember we are talking about the 99% of human history spent as hunter-gatherers.  I'm also leaving out many nuances; this is a bird's eye view.] 

Human males are one of the more involved with their offspring, and they form bonds and attachments to their young, which makes sense because human infants require such a huge investment.  Another species that behaves similarly to humans in this respect is canines.  In the wild, male wolves will range far from the pack to find food and bring it back to their mate and offspring.  They will also spend time playing with their pups.  There are also a couple of primate species where the males will carry, groom and play with their young. 

How does this relate to breastfeeding?  As you can probably surmise, males don't have a role in that, biologically speaking.  They provide food, shelter and protection to the female so she can breastfeed.  No, bottle feeding is not "natural."  But that doesn't mean it should never be done.  I'm not going to say it's just as good to bottle feed, even if it's breastmilk.  It's not.  Breastmilk comes out at the right temperature (mom's body can even run hotter or colder depending on what the infant needs) and is full of a mix of enzymes and antibodies perfectly suited to the infant's immediate environment.  Once breastmilk is frozen, many of the enzymes are destroyed.  And month's old milk doesn't provide antibodies to the germs your baby picked up at the grocery store this morning.  But that certainly doesn't mean it should never be done.

Bottle feeding is not a historically new concept.  Since the advent of pastoralism (and the domestication of animals), humans have been giving their babies other species' milk.  Archaeologists have discovered ancient bottles, so we know babies have been fed by artificial boobs long before our modern times.

We are genetically ancient beings living in a modern world.  There are no (or very few) selective pressures operating on our genes today.  It's quite easy in nearly every corner of the modern world to make it to reproductive age and have a baby.  Our biology is at sometimes at odds with our environment.  We expect our babies to fit into our modern lives; we don't want to change our lives to accommodate our babies.  We certainly don't want to be manipulated by our babies (I say this tongue in cheek; I don't think our babies are capable of manipulating us, but it is laughable and sad that my own pediatrician told me this when Avery was only about 4 months old - that if I nurse her at night any more, she is just manipulating me into being a human pacifier).

Our modern baby gadgets - formula, bottles, swings, bouncy seats, pacifiers - are convenient for us as parents, but to the baby, they are second fiddle to nursing at the breast, being worn in a sling next to your heart, gentle motion, and sleeping with mom.

I'm not suggesting you need to be a martyr for your children.  I only want to point out some aspects of human biology that might explain why your infant behaves the way she does and help guide your responses.  At the end of the day, you will follow your own instincts about parenting your own baby.  You still live in the modern world and there are likely going to be times when you make compromises between what is best for your baby and what is best for you.  There are going to be times when you want to give your baby a bottle, whether it's because you've decided to return to work, or just because you want to go out for a while without your baby.  And either way, it's ok to do that.

For me, after Avery was about six weeks old, I started pumping milk to give her bottles.  I was pretty sure I wasn't going to go back to work, but I thought Adam might be able to give her a bottle occasionally at night or in the early morning so I could sleep, or maybe on a weekend so I could go shopping by myself.  She drank milk from a bottle ONE TIME.  That was it.  We tried for months - not every day, but maybe a few times a week or every other week - and she just never wanted to drink from the bottle.  Admittedly, we didn't push the issue since we hated seeing her upset or crying when I could so easily just feed her from the breast and she would be happy.  Would she eventually have taken a bottle if forced?  Probably.  But in the end we weren't willing to put her through that.  (And her reticence to drink from a bottle, plus my reticence to see her upset, WAS a factor in my decision to stay home.  It wasn't the only thing, or even the most important...)  After I decided not to return to work, our efforts petered out and I haven't pumped milk in probably six months.  The same went with the pacifier.  She never wanted it, and we never forced the issue because we were heartbroken to see her cry so pitifully when I could just nurse her (as nature intended) and pacify her.  If Avery would have taken a bottle, I would have happily let Adam feed her sometimes.  If she had taken a pacifier, I would have probably used it at times - like at night or in the car.  (Now I don't mind that she doesn't take a pacifier because I don't have to wean her off it.)

Now I need to wrap this up because my little cave-ling is upset that I'm typing instead of paying attention to her!

Thoughts?  Comments?  Let me hear them!!

1 comment:

nicknmegan said...

Hey - thanks Michelle! Very interesting. You're so smart, and such a great writer. Nick and I devour every post and then talk about the topics you raise. Very useful for about-to-be first-time parents. I often wonder about the nexus between nature and society, since it's my impression that sometimes people tend to characterize all things societal or cultural as artificial, when really it's not that simple. To me, societal/cultural norms are often a manifestation of pre-existing biological traits or tendencies that we just naturally possess. I'm sure much greater thinkers than me have tackled this topic at length, and more eloquently than I ever could. Suffice it say, my take-away is that just because bottle-feeding isn't straight from mom's boob doesn't make it "unnatural" or wrong, but in fact might actually be a product of mankind's pre-disposed ability to adapt to his environment, as evidenced by the discovery of ancient bottles, etc. That said, IMHO, bottle- or formula-feeding out of convenience versus bottle-feeding out of necessity crosses that line from natural to artificial, and is something that I will aspire to minimize, though I'm sure I won't score a perfect 10, since I'm the queen of shortcuts. And sometimes convenience wins out. But anyway, that was a great post. The photo of the peacock was a nice touch. :)