Throwing the umpteen-hundredth
shovelful of show yesterday I almost injured our dog.
She wanted to move around, and there was no place a dog that small could
move except where I had shoveled, so as I advanced down the driveway, she was
there, too.
For a moment I couldn’t believe
she would put herself heedlessly in harm’s way as I sought to throw the snow with
sufficient force to get it over a shoulder-high snow pile. She was utterly clueless. Then I thought, of course! Golda has no experience
of throwing, not the force, not the arc, not the speed, not the momentum--since SHE could never
throw!
Then it occurred to me what a rare
ability we have: since grasping hands and opposable thumbs are pretty much limited
to primates, and the peculiar shoulder structure to make accurate distance
throwing appears to be limited to humans, no other creature would understand
it.
--which I looked up to see if I was remembering that right. We do indeed have an unusual shoulder, but a whole suite of other features help, also. And these aren't uniquely human (even if we're the only remaining species possessing them), since these adaptations first come together about two million years ago in Homo erectus.
And that is why even the strongest chimpanzee will never throw a hundred-mile-per-hour fast ball.
Model
of elastic energy storage.
NT
Roach et
al. Nature 498,
483-486 (2013) doi:10.1038/nature12267
No comments:
Post a Comment