Tuesday, January 12, 2010

Why I don't Have Monkey Feet

Ok. I may have too much time to think about junk like this but I know why we don't have feet more like monkeys. Monkey feet are awesome and superior in so many ways! A monkey can hold food and grab branches with them. That would be very useful imo. It would be so cool to be lounging at a bar somewhere with a cold frosty mug held by my foot while my hands are free to run through my fine dew.

Realistically I doubt you’ve ever wondered why humans don’t have long, prehensile toes that would turn our feet into extra hands but i'm gonna tell you anyway -- it's because our stubby toes are custom-made for running!

If we had long toes like monkeys, although we could write our grocery list out with our feet (hey honey, you think my handwritings bad just imagine how bad my footwriting would be), it would require so much more energy to run and generate more shock than short toes. Our stubs are one of many cool adaptations that have helped our Savannah-banana dwelling ancestors chase their prey. Being the fattest back then was no doubt VERY sexy. It was a sign that you were a good provider. Hey babe....you can't see my ribs! Short toes made the blubber easier to get at (not to mention farming and then McDonald's but that's another story)

Most primates — including our closest relative, the chimpanzee — have proportionately longer toes than humans. Ours are dwarfish and two-dimensional digits are capable only of extending and flexing. Most animals that run, also have extremely short toes. Dog's and cats have paws composed almost entirely of palms.

Fat Bastard (pictured above) would have been the Bill Gates of the stone age! Today, thanks largely to McDonald's he's a dime a dozen.

The importance of running to early Homo (and by early homo I don't mean Schroff'y AM jog) is, of course, conjectural. But it does make sense: few other animals are capable of long-distance running, and none can do so under a blazing sun. (Wolves and hyenas, for example, require cold weather or nightfall for long-distance hunting; otherwise they overheat.) Endurance running might have set early humans apart from the pack.

Our anatomical stub toe features make lots of sense in the context of savannah hunts-marathons. Other advances like our achilles tendons that act as springs to store energy, our hind limbs have extra-large joints not to mention our hairless buttocks with muscles perfect for stabilization (and very sexy I might add). In addition we have regions of our brains uniquely sensitive to the physical pitching generated by the motion of running -- ahhh the runners high!

Our stubby toes must have been all the primate rage back in the day's when youtube was just a dance recalled by memory in front of a tree.

So accordingly, we humans are tricked out for endurance running. Running a LOOONG way is much of what makes the human body the sucess story it is. And running far, we are the best long distance animals, is our specialty not speed. From the animal perspective, we’re actually terrible sprinters. So don't ever try to outrun that tiger! They don't even have toes. HA --Helgeson tastes like chicken.

Running is very different from walking. During the moment of propulsion, when one foot is in the air and the other is on the ground, between one-half and three-quarters of a body’s weight falls squarely on the forefoot. When you’re walking, before you push off to start the next step, your other foot has already hit the ground. You’ve transferred some of your body weight. Your toes have to do much more work in running, to push you.

If we had monkey like feet we'd be screwed. Increasing toe length by just 20 percent produces a doubling of motor force. Think about the action of a see-saw: levering force is magnified by the distance between pressure and a fulcrum. Also the longer toes require an additional energy investment when "braking," or using them to guide the forward-falling motion that underlies both running and walking.

The additional work required by long toes, and a resulting increase in muscle stress and damage, likely made those freaky feet cousings of ours a victim of natural selection.

So how did our ancestors, those weak little primates, kill big animals?
The answer is that we chased them. We made them gallop. They can’t pant and gallop at the same time. We can run down a gazelle not through speed, but through endurance!

Of course, in the modern world of grocery stores and restaurants, long-distance running is a recreational activity, and hard-soled shoes absorb much of the shock felt by a bare foot. Freed from ancient evolutionary pressures, what will happen to our feet?

It’s too soon to tell, and nothing at all may happen, but that’s generally a question you could ask about many features of the human anatomy and I'll talk about some that perhaps in another post.

My prediction -- the pinky toe is doomed! Kramer from Seinfeld disagrees

It isn’t required to push off, there’s talk in Vegas about whether the useless toe is eventually just going to disappear. Who knows. But don't bet it all on the one that went wewewewe all the way home!

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