Striped shore crabs (Pachygrapsus crassipes) live along the west coast of North America, from Baja California, Mexico, to central Oregon. Measuring 4 – 5 cm across the carapace, they can be found in estuaries, tide pools, mussel beds, or scuttling along shoreline rocks. These, and hermit crabs, are the most common crustaceans I see at my local tide pools.

Though they feed mostly on algae and phytoplankton, they are opportunistic and will also eat animals including dead fish, limpets, snails, isopods, worms, and mussels. They will even eat recently molted specimens of their own species. They are prey for seagulls, octopuses, rats, raccoons, and humans.

Though most crabs and many shore crabs spend the majority of their time underwater, P. crassipes is an exception. They apparently spend more than half their time on land, though they typically stay close to the water’s edge.