I found this cool creature while tidepooling on the California Coast. Crabs come in many shapes and sizes, but they have a few things in common – usually ten jointed legs and eyes at the ends of short stalks.
The Purple Shore Crab can be found sheltering under rocks in inter-tidal areas along the west coast of North America. They are quite adaptable, being found from the frigid shores of Alaska all the way to the sunny beaches of Baja California.
These crustaceans look for food during low tide at night on top of rocks and on nearby sandy beaches. They feed on green algae, snail eggs, smaller animals and more. On the flip side, for their part, they’re eaten by scoters (a type of sea duck), fish and gulls.
Purple Shore Crabs are rarely found in water deeper than three feet. They prefer rocky coastlines where hiding places are plentiful, because they do not burrow in sand, like many other crabs.
They have the ability to regulate the amount of salt in their systems, a trait called osmoregulation. This enables them to live rather far into brackish estuaries and salt marshes, where the the level of salt in the water changes with the tides.
The mating ritual of purple shore crabs involves a bizarre dance during which males and females rise up and embrace, belly to belly. The males clasp females firmly with their legs and claws, and fall over backwards.
The Purple Shore Crab truly was a fun find on my California trip.