ant strength v human strengh - Biologists v physicists!?

Question

OK, I asked this question earlier but placed it under the biology heading and got some wrong answers. Physicists please do better. I'm not necessarily after a quantatative answer. Here goes...
Ant body parts are designed for their size. They look spindly because of the ratio of body mass to cross sectional area is low. Coz we are bigger, we need more cross sectional area to support our mass.

So, if an ant can carry say 5 times its body weight, then if we were shrunk down to ant size (but our body proportions remained the same), how many times our own body weight could we lift?

Answer 1

I always dislike reading these things about how bugs are so super strong. It is a question of proportion. The weight of a muscle goes up with the cube of the size. Double the size of an animal and the weight goes up 8 times.

Muscular strength, however, depends on (I believe) the cross section of the muscle, so it goes up as the square. This means a strength goes up slower than weight, so eventually the weight becomes too much for the muscles to carry.

I saw a giant on TV a few days ago - 7'10". He could barely walk, using a cane. The human body is not designed for these extreme sizes.

All animals hit the same limits. I have read that when they compute the largest size possible for a bird to fly it was almost exactly the size of a condor. Elephants also are near the limit, which is why there is nothing bigger than them.

The same type of argument works in other ways as well. I read recently that the limit in insect size is due to the way they transport oxygen through their bodies. As the size increases it gets harder to do, ans again when they calculate the size they found the goliath beetle is just about the maximum size. If conditions change this can change too - the huge insects they had in the Jurassic were possible because the concentration of oxygen in the air was about double what it is now, so the maximum size was larger.

So, the answer is that with out build we could not shrink down to ant size. If an ant were expanded to our size it would quickly die of suffocation, but in its short life probably not even have the strength to stand up, much less lift some large times its own weight.

Answer 2

Ant To Human Ratio