Saturday, April 21, 2007

Endurance/Persistence running

Razib has a post on a story about a recent talk by Daniel Lieberman. Also see: here, here.

excerpts:

"Specifically, we developed long, springy tendons in our legs and feet that function like large elastics, storing energy and releasing it with each running stride, reducing the amount of energy it takes to take another step. There are also several adaptations to help keep our bodies stable as we run, such as the way we counterbalance each step with an arm swing, our large butt muscles that hold our upper bodies upright, and an elastic ligament in our neck to help keep our head steady.

Even the human waist, thinner and more flexible than that of our primate relatives allows us to twist our upper bodies as we run to counterbalance the slightly-off-center forces exerted as we stride with each leg.

Once humans start running, it only takes a bit more energy for us to run faster, Lieberman said. Other animals, on the other hand, expend a lot more energy as they speed up, particularly when they switch from a trot to a gallop, which most animals cannot maintain over long distances.

While animals get rid of excess heat by panting, they can’t pant when they gallop, Lieberman said. That means that to run a prey animal into the ground, ancient humans didn’t have to run further than the animal could trot and didn’t have to run faster than the animal could gallop. All they had to do is to run faster, for longer periods of time, than the slowest speed at which the animal started to gallop.

All together, Lieberman said, these adaptations allowed us to relentlessly pursue game in the hottest part of the day when most animals rest. Lieberman said humans likely practiced persistence hunting, chasing a game animal during the heat of the day, making it run faster than it could maintain, tracking and flushing it if it tried to rest, and repeating the process until the animal literally overheated and collapsed.

Lieberman said he envisions an evolutionary scenario where humans began eating meat as scavengers. Over time, evolution favored scavenging humans who could run faster to the site of a kill and eventually allowed us to evolve into persistence hunters. Evolution likely continued to favor better runners until projectile weapons made running less important relatively recently in our history. "

5 comments:

jwag13 said...

I think this is one of the more ridiculous ideas to come along. How does running long distances in the savannah square with the fact that humans are the least efficient terrestrial animal at conserving water (profuse sweating), and the fact that proto-hominids would have had to compete with a plio-pliestocene carnivore guild of giant hyenas & saber tooth tigers, not to mention all the friendlies that still survive there. A pernicious case of hubris IMO.

Yann Klimentidis said...

we know that at least one group of hunters do it today.
"least efficient...at conserving water", or could it be - very effective at using water to reduce heating?

jwag13 said...

"...one group of hunters do it today." - yes, but this claims to account for how pre-humans started to acquire meat, not what modern hss are doing today.

"..could it be - very effective at using water to reduce heating?" - a thin veneer of moisture is the most effective for air cooling (like a horse) but profuse sweating (as much as 15L/per day in humans) would seem to be a very poor adaptation to arid, terrestrial environments.

Cam said...

jwag, your a dumb fuck, try reading a bit.

Viagra Online said...

if you think about it, just the fact that we, well our ancestors, were able to run and keep running more than the animals represented a huge advantage and it catapulted the our ancestors in the food cain

 
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