[ExI] ai is the easy road

[spike at rainier66.com]

-----Original Message-----
From: extropy-chat <extropy-chat-bounces at lists.extropy.org> On Behalf Of Ben
Zaiboc via extropy-chat
Sent: Sunday, 18 October, 2026 12:53 AM
To: extropy-chat at lists.extropy.org
Cc: Ben Zaiboc <benzaiboc at proton.me>
Subject: Re: [ExI] ai is the easy road

On 17/10/2026 22:35, John K Clark wrote:
> Yes but I don't see why Bipedal walking would be better at endurance than
quadratic walking, if anything the reverse would seem more likely to me. 


>...I've wondered this myself before, but it seems to be true. I put it to
the test, years ago, with a friend's dog. ...

Dogs don't do as well in the heat because their primary heat loss mechanism
is evaporation off of the lungs.  Their panting isn't from running short of
breath, but from needing to cool.

>...Perhaps quadripeds are better at speed, but humans seem better adapted
for steady, long-distance running. Perhaps there's a psychological aspect as
well. I think wolves can patiently trot and wear prey down in a similar
way...

Wolf packs can work together to benefit each other and (maybe) other wolf
packs using the mechanism I wrote about earlier.  The notion of trotting to
save energy is compelling, but they are still range limited because of the
configuration of the legs.  If you look at a dog's hind leg, it almost looks
like it is on there backwards, with the knee bending the wrong way.  But
once you look closely, you realize their "knees" and "ankles" are analogous
to ours, with differing proportions.  Their foot is much longer, then their
joint where our knee is located is actually the joint analogous to our
ankle.  Their knee bends the same way ours does.

The consequence of this configuration is that they stand much less
efficiently than we do: it would be analogous to our standing on the toes.
Tense muscles use energy even if they are not doing any work.  Dogs use more
energy just standing than we do.

Note that dogs just process a lot of energy.  If you have one, note the
weight of the food you must lug around compared to their own weight, then
recognize they generally eat dry food, analogous to our backpacking food,
which is designed to be light.  If your pampered pet gets canned food
(analogous to ours), note the ratio of food weight to dog weight.

>... so maybe it's just that most prey animals are wired to run off as fast
as possible, which wears them out quickly... Ben

Or overheats them.  Think scale.  If you scale up a beast, its volume to
surface ratio scales up linearly.

>...Looking at the biomechanics, being tall, with 2 legs, might be more
efficient for running than being short with 4 legs. With bipeds, gravity
does some of the work, which is not so with quadrupeds, or a lot less so....

Since we are considering what mutation came first, one could plausibly
suggest the locking knee.  With the knee straight, humans can stand and walk
very efficiently: no muscles need to be continuously locked.  The other
great apes do not have the locking knee.

I knew a girl who was born without locking knees.  She could walk but only
short distances and it was exhausting for her because the large thigh
muscles were always working.

spike

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