Friday, August 26, 2011

Aww…look, our quadruped is becoming a biped! Or, look who’s walking now!

Every parent wants their kid to achieve the ‘milestones’.  We put so much pressure on them.  “Does he hold his head up yet?”; “Can she roll over yet?”; “Does he crawl?”; “Does she walk?”; “Does he talk?”  “Is she potty trained?” “Does he have a diversified portfolio and an IRA?” 

But walking—that transition from 4 legs to 2 legs—seems to be one of the biggest milestones of early childhood.  When we make that symbolic transition from the animal world to the human world. 

Turns out that other than birds and dinosaurs, there are very few groups of vertebrates that habitually walk on two legs instead of four.  Kangaroos, some groups of mice and rats, and people.  And several other groups will walk on two legs when they really need to, like deer reaching up high for a branch that’s too high or lizards running on water

So, why have we eschewed the 4-legged world for two?  There are many dozens of theories in the evolutionary literature for why humans have moved more and more towards two-legged walking even though our very closely related cousins still prefer all fours—the Wikipedia entry on the matter is surprisingly thorough!. These theories range from the
aquatic ape hypothesis’, whereby our ancestors were adept waders and swimmers and this lead to our bipedalism to keep our heads above water (this hypothesis appears to be believed by about 4 people) to other more well-accepted theories, including the ‘male provisioning hypothesis’.  Here, the idea is that a good man goes out to hunt or gather, gets as much food as he can, and has to carry it all the way back to where his wife and kids are chilling out.  Remember, this is before the dawn of backpacks and wheeled luggage—and certainly before the time of the stay-at-home-dad.  So, these dudes had to carry the food home either in their hands or in their mouths.  Well, if you’ve ever tried to carry a big load of stuff around with you in your mouth or while crawling around on all fours, you’ll see the problem.  Much better to hold it and walk on your hind limbs—or legs.  So, there you have it, a pretty good reason to walk on two legs.  To bring home the bacon (so to speak).

Jack’s always been a bit ahead on his milestones, and we’re always so proud…as if somehow he’s smarter and more talented than the kids down the street.  “Hmmmm..little Joey doesn’t crawl yet?  What a shame…Might as well forget about college”.  Jack was well into standing and ‘cruising’ along on furniture at 8 months, and we thought he was going to take off walking soon thereafter.  His mom, after all, was walking at 9 months. 

So, 9 months comes and goes…still no walking.

10 months….lots more cruising, but still not walking.  Uh oh, maybe he’s not as exceptional as we thought?

11 months.  Now Jack’s getting very interactive with the world around him.  Much less a blob and much more a little boy.  He’s got toys, he’s able to drink from a sippy cup, he’s got his snacks!  But, he’s got to crawl around with them, which sucks if you want to be in the other room where your dad is doing cool stuff (like washing the dishes), but you want to bring your toys and snacks and sippy-cup with you. 

So, here’s where I think I can really see the merit in the idea that we walk on two legs because we need to get stuff from here to there.  Sure, he’d crawl around with a toy in his mouth or hand…and it was cute, but very inefficient.  I think he’s been thinking: “if I have stuff in two hands, I can bring twice as much stuff into the kitchen to play with/eat/drink”. 

Over the past few weeks, Jack’s determination to learn how to walk—so he can take stuff with him—has been amazing.  From one or two tentative steps to full blown walking around the house in just a couple of weeks.  If you have a minute, check out the videos taken of him every 4-5 days for the past few weeks.

He’s mastered it!  Now he can carry his stacking cups around the house; Now he can carry his baby cheetos around the house; Now he is a man!

So, there you have it….watching Jack learn to walk has given me definitive proof that humans have evolved bipedalism in order to get their stuff more easily from point A to point B.  Class dismissed.

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