At first glance, a rocky beach on Puget Sound may seem home to few creatures, but that's far from true. Gently overturn a rock, and you'll often spot one of the beach's most abundant residents: the Purple Shore Crab. Watch closely because the lively purple shore crabs scuttle quickly away and vanish.

If you're lucky, you'll glimpse this crab long enough to see that its shell is almost square. The color in its name isn't completely accurate because the crab's body varies from olive-green to red to deep purple. Tell this species from similar ones by its hairless legs and its white-tipped claws marked with purple or red spots.

Even full-grown, these shore crabs are just 2 inches across. That's bite-sized for a gull, so until nightfall these little crabs hide under rocks where gulls can't see them. After dark, the crabs venture out to eat seaweed and bits of dead animals.

One female shore crab can lay over 36,000 eggs in a single year. The abundance of shore crabs makes them an important clean-up crew on the beach.

Purple Shore Crabs are mostly vegetarian, but be rough with them and they'll give you a good nip with that big right claw. If you do pick one up, be sure to carefully return it to its hiding place and gently replace the rock. That's home-sweet-home for this important member of the intertidal community and for many other creatures too.