The Strength of Ants

I captured the above video the other day while I was eating a sandwich and it really does highlight the perceivably super-hymenopteran strength of those remarkable little creatures that we like to call ants. I dropped a piece of pickled jalapeño pepper onto the footpath while I was eating and thought nothing of it at the time but looking down several minutes later I saw a green ant walking backwards dragging the comparatively massive jalapeño between its mandibles. Several times in the video you can see additional ants looking like they want to help drag the pepper but receiving only a kick of the back leg from our hero ant for their concern. Anthropomorphisms aside, lets examine whether this great feat is actually something that is worthy of our awe and admiration, or just something that becomes substantially less impressive once we look at the physics behind it.

It may or may not be a fact (depending on who you ask) that ants in general can lift about 50 times their own body weight. For a large ant 1cm long that only weighs about 2 hundreds of a gram this means it could carry about a of a gram of jalapeño. Lets compare this to a 180cm tall, 80kg human man who doesn’t really work out too much and can only lift at most about 40kg or half his body weight. Now at first glance it appears that ants are the stronger of the two taking into account the difference in size.

But to have a really fair contest we want to hypothetically scale the ant to the size of a human. The human weighs a whopping 4,000,000 times more than the ant, would an 80kg ant still be able to lift 50 times it’s own body weight, the equivalent of 4 metric tonnes of jalapeño? Or would the laws of physics come raining down on its parade?

Muscle strength is proportional to the surface area to volume ratio of a muscle. Unfortunately for the ant, every time it doubles in size this surface area to volume ratio is decreased by 50%. To make a human sized ant we need to double the length of the ant about seven and a half times to get an ant about 180cm long. We can express the potential lifting power of an 80kg ant as 80,000g of ant x 1g lifting power x 0.5^7.5 power reduction due to length = 442g.

Alas the muscles of our not-so-puny big ant end up only being able to carry a minute 442 grams. Which is the equivalent of a human not being able to lift a pint of water, it’s very likely that a human sized ant would collapse under its own body weight. It’s quite striking to note that while a life-sized ant can carry a slice of jalapeño, a human-sized ant would struggle to carry a single large jar of jalapeños.