Hermit Crabs just love their shells. But they don't get attached, because as they grow, the soft-bellied crabs need to swap out their borrowed homes for new shells, allowing a smaller crab to take the used abode. This real estate bargain takes place in coastal waters worldwide. Characteristics: Looking fine in their borrowed shells, these Hermit Crabs are ready to join an ocean-themed party or school unit as giveaways, study tools, or prizes.