Hermit crabs are invertebrates. The body clings to the exoskeleton, an outer shell, which plays little role in protection against predators. Hermit crabs use other invertebrate's old shells for protection. They vary in color and in patterns. They move by aid of ten legs. The front legs are big, and they have claws (pincers or chelipeds). Rear legs are very small. Sensory organs include eyes on stalks and antennae.