Here and there are calm pools of water with seaweeds lining their walls and casting deep shadows. Limpets, barnacles, and periwinkles live on the bottom. Among the barnacles cluster small specimens of mussels; these same mussels become larger and more abundant in the Middle Tide Zone.
The hermit crabs will probably attract attention first, amusing creatures which never lose interest in their lifelong search for a suitable home. Because their lower abdomen is soft and curled, as they grow they must constantly find larger shells to protect their bodies. The hermits, therefore, often fight vicious-looking battles over empty snail shells. If time permits, a hermit will grasp the new shell, turn it around, tap it with the antennae, and look inside. The inspection completed, the hermit quickly hops out of the old shell and slides tail first into the new one, and uses hook-like appendages for holding onto the "shellhouse" and the large claws for blocking the entrance to the shell.
Several species of hermit crabs occur intertidally, but two occur most frequently in the High Tide Zone. One of the more common species is the Hairy Hermit Crab, Pagurus hirsutiusculus, recognized by its hairiness and by the white or blue band around the base of the legs of larger specimens. Along with the Hairy Hermit Crab, but becoming more abundant lower down on the shore, the Granular Hermit Crab, Pagurus granosimanus, is about the same size as the Hairy Hermit but is almost hairless. Its pinchers are rough and granular, its legs spotted with white or blue bands, its antennae red.