A hermit crab is a small crustacean that belongs to the family Coenobitidae. Unlike true crabs, hermit crabs do not have a hard shell. Instead, they use empty shells from other sea creatures, such as snails, to protect their soft bodies. As they grow, they will search for larger shells to move into. Hermit crabs are often found in coastal areas and can be both terrestrial and marine. They are social animals and can live in groups. Hermit crabs are scavengers, feeding on a variety of organic materials, including decaying plant matter and small invertebrates.