These are tent caterpillars that form a line to go anywhere. If you take off the first one and put him on the end the second one does not know what to do and stops and all the others crash into the caterpillar in front until it is just total chaos. Then they elect a new leader and make a new line. This probably comes down from Greece's golden age of democracy and is yet another important piece of evidence that man is related to the caterpillar.