With all those legs, why can’t caterpillars run?
Caterpillars are larvae of butterflies or moths, and like other arthropods,
they don’t have any bones in their body.
While it may look like they have lots and lots of legs, only six of those are really legs;
the rest are stumpy little appendages called “prolegs.”
They move by squeezing muscles in sequence in an undulating wave motion,
and their legs and prolegs help them with traction.
Place your hand on a table or other flat surface, lift the heel of your hand, and inch it toward your fingers and you’ll have a pretty good sense of how caterpillars get around.
Their movement creates a “wave” that moves from back to front, propelling the critter forward.
So even though some caterpillars can move pretty quickly, they can’t truly run.
See for yourself: Cruising for Caterpillars!
In your backyard, a nearby park, or forest preserve, go hunting for caterpillars.
The best place to find them is on the undersides of leaves – look for leaves with holes chewed through them,
as this is a clue that caterpillars might be nearby.
If you find one, try to carefully remove it from the plant without touching it directly (some caterpillars have stinging hairs that they use to defend against predators, and these can really hurt, so gently use a leaf or a small stick), and set them down on the ground.
Can you see the “wave” of its body as it crawls away?
If you have a jar or other small container with a lid, you can try to gently nudge the crawly creature
inside to examine it more carefully, but when you’re done you should put it back where you found it,
so it can grow up to become a butterfly!
