The picture (left) from the University of Cambridge shows a 5 milligram ant lifting a 500 milligram weight while dangling from the ceiling. It's unclear from the picture if the ant would be able to actually lift the weight off of the ground and technically carry it and not just drag it, but considering that he is able to lift that much weight while upside down from the ceiling we'll give him the benefit of the doubt. Even being able to drag that much weight is impressive. How many of us can drag something 100 times our own body weight without wheels?
How much is that in Human terms?
The average American male weighs approximately 177 lbs. (wikipedia, 2013). So in order to lift 100 times their body weight, a person would need to lift 17,700 lbs. (177lbs x 100 = 17,700). That's about the size of a school bus. It would be a hard enough task to simply drag the school bus, let alone lifting the bus over your head and carrying it around all day like the ant does.
Why are Ants so strong?
Generally speaking smaller organisms will always have a higher strength-to-weight ratio than larger organisms. The answer has to do with the physics of size, mass, and strength.
- The strength of a muscle is proportional to the surface area of its cross section. (Cross section - A surface or shape that would be exposed by making a straight cut through it).
- Surface area is a two-dimensional measurement, and is proportional to its length by a factor of 2.
- Volume is a three-dimensional measurement, and is proportional to its length by a factor of 3.
What that means is that larger animals have a greater disparity between mass and strength, because the larger an animal is, the more mass the animal has compared to muscle. When a large animal needs to lift an object, its muscles must also move a greater volume, or mass, of its own body (about.com,2012).
A easier explanation might be to imagine 3 cubes. The inside of the cube represents the weight of the animal, and the outside of the cube (surface area = 6 sides of the cube) represents it's muscles.
- The first cube represents an ant. Let's say it is a 2 inch cube (2x2x2). It has a weight/mass of 8 cubic inches (2x2x2=8), and it has a surface/muscle area of 24 square inches (2x2x6=24). The ants weight to muscle ratio is 8/24. The ant has 3 times the muscle area than it's weight.
- The second cube represents a bigger animal. This one is a 5 inch cube (5x5x5). It has a weight/mass of 125 cubic inches (5x5x5=125), and it has a surface/muscle area of 150 square inches (5x5x6=150). This animals weight to muscle ratio is 125/150. Way less than what the ant had and it's only a little bit bigger cube.
- The last cube will represent a human. Let's say it is a 10 inch cube (10x10x10). It has a weight/mass of 1000 cubic inches (10x10x10=1000), and has a surface/muscle area of 600 square inches (10x10x6=600). The humans weight to muscle ratio is 1000/600. The amount of mass has now exceeded the amount of muscle, and it get's worse the larger the animal gets.
Considering that a person weighs 29 million times more than an ant, the weight to muscle ratio is going to be considerable higher.