Lined Shore Crab Pachygrapsus crassipes One of the most active organisms found in the splash and spray zone is the Purple Shore Crab. To grow, crabs must periodically shed their shell (molt). You may  find these intact deserted shells along the beach. To escape enemies, crabs can shed their legs or claws. Lost parts can be regenerated after a few molts. Most crabs are scavangers that feed on bits of seaweed and other small organisms. Some of the predators that eat crabs are fish, birds, and octopi. Habitat/Range: Purple Shore Crabs live in crevices and under rocks along the shore from Oregon to Baja California.