Dear Dr. Universe: I would like to find out how ants are so strong. How is it possible that they can carry weight that is heavier than themselves?
Ants are pretty good little weightlifters. My friend Rich Zack, a scientist at Washington State University who studies insects, knows a lot about ants. One kind of ant that he has studied can carry up to 20 times its own weight.
Ants don’t have special muscles that give them super strength. In fact, their muscles are actually quite a bit like the muscles of other animals.
Zack explained that we often think about strength as the ability of an animal to carry something heavy. Ants can lift big sticks, leaves, and some can even carry a full-grown grasshopper. Of course, they couldn’t lift a fork at the dinner table like you can. Their strength is all relative to their size.
One thing we can look at is the animal’s volume, or the amount of space something takes up. Then, there’s the surface area of the object. When we measure the outside of an ant’s body we can find its surface area.
As you observed, a regular-sized ant is able to lift things much heavier than itself. But what if we doubled the size of the ant? Do you think the ant might get even stronger?
“An ant the size of your house would have much more absolute strength than a regular-sized ant,” Rodgers said. “However, it could no longer lift 50 or so times its weight and the small ant would be stronger, relatively.”
If we doubled the size of an ant, the surface area of the ant would also double. But its volume would actually more than double. This is an idea that holds true with pretty much all objects. If things appear twice as big, they actually weigh more than twice as much.
You may have also heard ants wear their skeletons on the outside. Their muscles don’t have to support such a heavy skeleton, so they can instead use their strength to help carry other things.
Ants and other insects have a large surface area compared to their volume. And the muscle strength of an animal is pretty closely related to surface area, Rodgers said. Yes, it’s true ants are strong. But it’s all compared to their size.
There are actually some insects that, for their size, are even stronger than ants. Do you know what insect that might be? Send me your best guess at Dr.Universe@wsu.edu for a chance to win a Dr. Universe sticker.
Try it out! You can explore area with a fun, simple activity. Print your own graph paper and make your own pop-up paper creature. Can you find its surface area?