"How much weight can an ant lift?"

Ants can lift anywhere from 20 to 50 times their body weight. The smallest ant that I know of weighs about 0.00001 g, or 0.000000022 lbs. An average ant weighs about 0.004 grams, or 0.0000088 lbs. The largest ant measures up to 3.3 cm and (complete guess) weighs about 0.4 g. So figure that an ant can lift, for smallest, average, largest, can lift at least 0.002 g, 0.08 g and 8 g, respectively; and at most 0.005 g, 0.2 g, 20 g, respectively.

Ants of most species include workers, males and females. Workers are small, but strong. Workers of the Formica japonica ant weighing 0.004 g can walk while holding an object weighing 5 times the body weight in the mouth and can even drag a 25-times heavier object.

It's common knowledge that ants can lift many times their own weight. We are frequently told they can lift 10, 20, or even 50 times their weight. It is most often stated something like this: an ant can lift over its head objects that weigh 20 times what the ant weighs. This is the equivalent of a 220 pound (100 kilogram) man lifting over 4,400 pounds (2000 kilograms) over his head! Seems incredible, doesn't it? That's like lifting a new VW Beetle, with five big men inside, over your head. A person who could do that would be a superman!

Are ants superstrong then? No. The reason they can lift so much more than they weigh is because they are very small. If we were that small, we could do it too. A small animal lifting many times its weight is not the same as a large animal lifting many times its weight. The reason has to do with simple geometry and the characteristics of muscles.

As an animal, or any object, grows in size, its volume and weight increase much faster than its height. If a 220 lb (100 kg) man were to grow ten times taller, his weight would increase by a factor of 1000 (the cube of his height). He would weigh 220,000 lbs (100,000 kg)! The strength of his muscles, on the other hand, would increase by the square of his height, or by a factor of 100. He would be 100 times stronger but 1000 times heavier. His muscle strength could never grow as fast as his weight. It's simple geometry. There is little reason, then, to compare the strength of small animals to big animals when it comes to how much more than their weight they can lift.

That's a great question! If you look around on the internet, you'll find numerous references to ants being able to "lift up to 50 times their own weight", but nobody ever explains how, or where that number of "50 times" comes from. I haven't been able to find out where the number came from, but I can tell you why ants can lift so much.

The reason that ants can lift so much is because of scaling: ant muscles are no stronger than human muscles on a pull-for-pull basis, but the small size of ants gives them an advantage on how much muscle force they can produce.

A muscle is basically a bundle of fibres which can contract and create a pulling force- the amount of force produced by a muscle is proportional to the cross sectional area of that bundle of fibres. Consider a bundle of bungee cords- one bungee cord has a small cross sectional area, and doesn't exert much force (you wouldn't jump off a bridge with just one bungee cord to stop you!); a bundle of bungee cords, such as is used for bungee jumping, has a much greater cross sectional area, and exerts much more force (enough force to stop a bungee jumper from hitting the ground!). In human terms, you can think of a human bicep- the bigger the bicep, the larger the cross-sectional area, and the more force (or strength) that can be applied by that bicep. A fellow by the name of Wigglesworth, in 1972, looked at the strength of insect and vertebrate muscles, in terms of force per square centimetre, and found that they both exerted similar forces, so it's not that ant muscles are somehow stronger.

The reason that ants can lift so much is because body size (in terms of volume, which is closely related to mass) increases as a cube of length- while the cross sectional area of muscles increases as the square of length. So, as the size of an organism increases, its mass increases at a much greater rate than the cross-sectional area of its muscles, so those muscles have proportionately more mass to lift.

So, the reason ants can lift so much is because their small size means they don't have a large body mass that they must carry around- they have proportionately more muscle (in terms of that cross-sectional area) that they can use to lift heavy things. Conversely, humans are proportionately more massive, and have less muscle that can be applied to lifting heavy things. The diagram below will explain this:

You can see that as size increases from big to small, the difference between mass and the amount of force that can be produced by the muscles gets greater and greater. In effect then, we humans have all this extra mass we must lug around, and we have proportionately less muscle to apply force on it, which keeps us from being able to lift as much of our body weight as ants can.

Hope that helps!

 

---

 

 

 

---