The hermit crab is a type of crab that doesn't have a very hard shell. Not a true crab, it uses other animals' old shells for protection; they especially like old whelk shells. As the hermit crab grows in size, it must find a larger shell.

The hermit crab is a crustacean; there are about 500 different species of hermit crabs around the world. Most hermit crab species live on the ocean floor, but many live on land. Female terrestrial (land based) hermit crabs must return to the sea to breed.

Anatomy: Hermit crabs are invertebrates, animals without a backbone. They have an exoskeleton, an outer shell that provides support for their body but does not provide much protection from predators. They vary widely in color, from red to brown to purple, with stripes, dots, and other patterns. They have ten jointed legs; the front two legs have large, grasping claws (called pincers or chelipeds) and the rear pair of legs are very small. They have a flattened body, sensory antennae, two eyes located at the ends of stalks, and a soft, twisted abdomen (which the hermit crab keeps hidden inside its shell).

Diet: Hermit crabs are omnivores (eating plants and animals) and scavengers (eating dead animals that they find). They eat worms, plankton, and organic debris.