Watch ants for any length of time, and you'll witness some remarkable feats of strength. Tiny ants, marching in lines, will haul food, grains of sand, and even small pebbles back to their colonies. It's true that ants can lift objects 50 times their own body weight. Why are ants so strong?
The real strength of an ant, or any insect for that matter, lies in its diminutive size. Generally speaking, the smaller the critter, the stronger it will be. It's physics, plain and simple.
First, you need to understand a few basic measurements of size, mass, and strength:
- The strength of a muscle is proportional to the surface area of its cross section.
- Surface area is a two-dimensional measurement, and is proportional to the square of its length.
- Volume is a three-dimensional measurement, and is proportional to the cube of its length.
An animal's weight is related to volume, which increases in proportion to the cube of its length, or by a factor of 3. But its strength is related to surface area, which only increases in proportion to the square of its length, or by a factor of 2. Larger animals have a greater disparity between mass and strength. When a large animal needs to lift an object, its muscles must also move a greater volume, or mass, of its own body.
The tiny ant has a strength advantage because of the ratio of surface area to volume. An ant need only lift a small measure of its own weight relative to the strength of its muscles.