Realities Created, Maintained and Destroyed, WHILE-U-WAIT!

Friday, October 02, 2009

Chasing Bambi

Steve Perry's reply to my last post

So, one thing at a time. First, the efficiency of run-down hunting.

Let's say me and five of my buddies, using your example as a for-instance, decide to get up tomorrow right and early and go run down Bambi for supper. I weigh 200, and since we aren't any of us Australopithecus, lets say we average 190 pounds, which makes plugging in the numbers easier.

If we spot the deer or the antelope playing and take off after it at a slow-and-steady pace, call it 8-minute miles (to qualify for Boston, you have to run sub-seven minute miles). Then we are going to burn 992 calories each, per hour. http://www.nutristrategy.com/activitylist3.htm .

Itty bitty guys will burn less, but I'm not an itty bitty guy.

Faster we go, more we burn.

If we are slow and it takes, say, six hours jogging along, then that means about 5900 calories each to get the critter. (And if it can walk as fast as we do, we'll never catch it unless we run; that only works in horror movies.)

Plus what it takes to walk home, assuming we ran in a straight line. (Walking is slower, but does burn fewer calories. For years, I believe that old saw that walking and running burn the same number of calories over the same distance. Not so. Faster you move, more you burn. Work might equal force through a distance, but there are other factors in a biological machine: http://www.runnersworld.com/article/0,7120,s6-242-304-311-8402-0,00.html)

If we are really fast and can do it in two hours? Then it costs us only a third as much energy. We'll do those numbers for the low end. (Though your Sun runner video -- in which the guy is wearing running shoes, I must point out -- took eight hours and ended with a spear, so it's maybe not quite the same, and yes, it was staged, unless they all hunt with British camera crews, but ...)

At six hours: So me 'n' my posse are apt to be tired and hungry once we catch up to Bambi. Going home at a pace equal to walking the dog, burns about 300 calories an hour, but it is going to take 2-1/2 times as long to get home, so we are looking at a fifteen-hour walk if we do it that way, and another 4500 calories each. Maybe want to hurry, since if we started at dawn and got Bambi at noon, fifteen hours is going have us walking around after dark with a dead and butchered critter slung over our shoulders, and we can't outrun Bagheera, no way, no how. So the faster we go, the more it costs us in energy.

At six hours: Each of us needs 10,400 calories to chase dinner down and get it home at three in the morning. Let's say we want to get home by dark, it's the summer, stays light until nine p.m. so we trot at five mph. That raises the calories needed, so call it 600/hr, for another nine hours.
Now: 5900 + 5400 = 11,300 calories burned chasing supper. Each.

At two hours: If we are really quick and do it in two hours and get home in four or five, then it's 1/3rd as much energy, and since the walk home won't take as long, call it 3000 calories each for the round trip. Iffy in my book, but for the sake of argument, let's say me and the boys are fleet. (I burn almost 3000 calories a day, and I hardly ever chase down deer on foot, so you have to figure the boys need as much a day as I do, and probably a bit more.)

At six hours: Lean venison (and pronghorn) is about 840 calories/pound. http://ces.uwyo.edu/PUBS/B920R.PDF Let's say we don't dress it, out but use the liver and kidneys and all, some of which are higher in calories, and kick it up a notch, call it 900 calories/pound overall. Tripe is less, liver is more. That means me and the guys need over 12 pounds of meat each to replace what we burned by the time we get home. 72 pounds.

At two hours: Ah, but we are fleet, and at a third of that, we need but 4 pounds each, 24 pounds total.

Average white-tail deer or pronghorn antelope runs about 80 pounds. Some of that will be lost to hooves and hide and horns and bones. There's a formula: http://www.askthemeatman.com/estimate_deer_weight.htm
So what you wind up with that is edible from an 80-pound deer? 35 pounds. Let's say you suck the marrow and keep the innards and those make another 10 pounds. Now to 45 pounds. After the boys and I chow down to keep from starving, we bring home a net 21 pounds of supper for the tribe. If we each have mates, a couple children, grannies and grampaws, call it twenty-five or so people at home to feed? Then they are on a lose-weight-fast diet.

Better be some gatherers in the tribe.

Steve

1 comment:

Anonymous said...

Mostly to one side, but maybe worth saying in re:
"Work might equal force through a distance, but there are other factors in a biological machine"

Work is force through the distance *in line with that force*; when gravity is the force you're fighting, only the up-and-down distances matter, not the distance-along-the-ground. If you're running on a flat plain, *only* those other factors contribute to the work.