I have never seen caterpillar's moving in formation like this, come to think of it I have never seen caterpillar like this at all.
Maybe all the rain has driven them out of their home, and now they were looking for a new one.
I wonder whether they move this way so nobody gets felt behind. They were not crawling over the top of each other. they just had their back half on top of the another and they all moved together.
The bearded dragon lizard was very impressed as well.