Terrestrial isopods are small, land-dwelling crustaceans belonging to the order Isopoda. They are commonly known as pillbugs or roly-polies and are characterized by their segmented bodies and hard exoskeletons. These creatures typically inhabit moist environments, such as under rocks, leaf litter, or decaying wood, where they help decompose organic matter. These isopods breathe through gills, which require a humid environment to function effectively. They are primarily detritivores, feeding on decaying plant material, and play a crucial role in nutrient cycling within ecosystems. Terrestrial isopods are found in various habitats worldwide, contributing to soil health and biodiversity.