Dear Antonia Malchik,

It is a very absorbing and well-researched article. I deliver a talk often on 'self-propelled movement'. Bipedalism also features in that. One should consider that we humans think that among other things, we have done two great things, millions of years ago: one that we started walking on two legs, freeing our hands for doing so many jobs, which were not otherwise possible, and two, for all the movement gadgets we invented the wheel. Both these things helped humans to evolve quickly over the rest of the living world, but kindly ponder over the following:

(A). Walking on two legs transferred untold weights and misery on our spinal cord. Nature had not designed the spinal cord for bipedalism. No wonder that humans, particularly at old age suffer all diseases of the spine, pelvic muscles, and knee pain, etc. and have to depend on wheel-chairs etc. in certain advanced cases of the SC-related wear and tear. Compare this with the heaviest of animals, whether it is a hippo or an elephant, they are quadrupeds with their spine located uppermost part of their body, ensuring that no body-weight is transferred to the spinal cord, while moving or standing etc.

(B). Nature never utilized any wheels for movement. Look at a huge variety of smallest to largest animals moving - no wheels. Humans, by depending on wheels have caused a huge wastage of fuels, say in an automobile. Not more than 5% of the energy produced in the internal combustion engine is used to move the driver (presuming traveling alone), the rest is wasted in moving the weight of the car itself, or to counter friction, or rejected by way of poor efficiency of the IC engine, and causing a lot of pollution, too.

Now you would say, by not adapting to bipedalism, all the advantage that the humans have vs-a-vis the rest of the living world, would be lost. NO, perhaps a biped-quadruped combined model (like monkeys) if evolved over millennia might have scored. And that would have meant a respite from all the diseases of the brain, since currently, the human body has the brain located on top, with the heart having to pump the blood (required in disproportionately large amounts to feed and service millions of neurons) against the gravity.

-- Prof. Dr. J.V. Yakhmi (ya_kmi@yahoo.com)