In a new study, biologists tracked thousands of California Lumbriculus variegatus worms acting as one organism. The results of the work will be useful in robotics.

California black worms (Lumbriculus variegatus) are a type of aquatic worm that usually grows no more than 4 cm in length. But when they are threatened by environmental factors, such as drought, individuals weave together to retain moisture and protect each other. The researchers also noticed an emergent collective movement in the worms.

In a new work, scientists have found that perfect balance, tenacity and wavy movements help worms move. The results can be used to develop soft robotics with many small and simple parts that work together.

Clusters of black worms essentially act as a non-Newtonian fluid or fluid that changes thickness depending on the nature of the force applied. A classic example of such a liquid is a mixture of cornstarch and water. Its viscosity increases in proportion to the force exerted on it. In other words, a whole group of worms, tightly attached to each other, acts like a solid, but if they “loosen up” a little, then the congestion of individuals looks more like a liquid.