If this article is to be believed worms form herds and influence each others behaviour often making group decisions. The findings come after researchers found that worms use touch to communicate. By doing so they often decide to collectively travel in the same direction. Researchers noticed the behaviour when they were looking at how earthworms interact with microorganisms in the soil. In doing so they noticed that the worms also seemed to interact with each other and often clustered together.

An experiment was set up to find out where earthworms decided to go and whether they liked to travel on their own or in groups. 40 worms were placed into a central chamber with two extended arms. The worms were left alone with a view to seeing how they moved over a 24 hour period. In most cases the worms preferred to group within one of the chambers over the other.

In a second experiment worms were placed in a soil filled maze with two routes to food sources to try and test whether worms affected each others behaviour. One worm was added to the maze and after it choose its route to the food source a second worm was also added to see if it followed the same route. After repeated trials it appeared that the worms were no more likely to follow the same route. However, when two worms were placed in the maze at the same time they were more likely to follow each other suggesting that they use touch to communicate where they are going. It is still not known why the worms herd together but it is thought it might be that clustering together helps them to protect themselves. Either way it seems we have a lot left to learn about the simple earthworm.