Little is known about the ecology of trilobites since the environments in which trilobites once lived have gone forever. We get information from some "tracks" or trace fossils. The information from organisms found nearby can also reveal the environment in which the trilobites lived. The picture shows that the movement of trilobites by using the trace fossils. The horseshoe crab in the middle is shown for comparing purpose.

A recent study (Pratt, 1998) used the data obtaining from a number of trilobite assembages to study the presence of disappearance of soft-bodied trilobite predators. By studying how the trilobite body parts was broken and distribution of them, he infers the presence of soft-bodied predators which is not readily perserved.