Definition: Detritivores are a group of animals that eat dead organic matter, for example, fallen trees, plants, or the bodies of animals that have died. They eat away at the surface of this material and break it down. This makes it easier for the decomposers to access and break it down further so that nutrients are released and can be returned to the soil. Detritivores are creatures like woodlice, earthworms, beetles and millipedes.