In order to move faster, caterpillars and some other insects form formations known as "rolling swarms" by crawling over each other.
Transcript:
RUDY MANCKE:
Hi, this is Rudy Mancke from University of South Carolina for NatureNotes.
Bruce Rogers and Lee Thomas, both, sent me pictures that they thought at first was one thing, almost like a snake. There was a lot of animals moving in the same direction at the same time in a line. When they look closely, there were caterpillars and a string of them. Fly larvae do the same thing.
It's referred to as a rolling swarm, and it increases the overall speed. If they're trying to cross an open area, heading toward a food source or just to get out of the bright sunlight. The bottom layer moves at the regular speed, the top layer is moving faster, kind of like an escalator. Because you can move faster if you're on top of that moving escalator. They swap positions a little bit too. It's a strange thing when you see it.
