Hermit crabs live in the empty shells of other species. Despite their name they are quite social animals.
Hermit crabs do not have a shell themselves. To protect themselves they move into the empty shell of other species. When they outgrow their mobile shelter they have to search for a new and bigger one. Since the shells are often not symmetrical the body of the hermit crabs adjusts to their home; thus one of their pincers is often bigger than the other. Hermit crabs are social creatures that hang out together in their natural habitat.