Terrestrial crustaceans are a group of crustaceans that have adapted to live on land rather than in water. They belong to various families, with the most well-known being isopods, such as the pillbug or roly-poly. These creatures have developed specialized respiratory systems to breathe air and often require moist environments to prevent dehydration. These crustaceans play important roles in their ecosystems, contributing to soil health by breaking down organic matter. They are typically found in leaf litter, under rocks, or in decaying wood, where they help recycle nutrients. Their adaptations allow them to thrive in terrestrial habitats while maintaining their aquatic ancestry.