Whether you’ve been tidepooling, beachcombing or have simply enjoyed a leisurely stroll on the sand, you have probably come upon a hermit crab or two! Hermit crabs are abundant in tidepools and along the seashore. They can be found living in abandoned marine snail (gastropod) shells and, less commonly, in other hollow objects (e.g., coral, rock or wood).
Look closely! Do you see the legs of the hermit crabs scooting around in this LaJolla tidepool?
Hermit Crabs in a La Jolla Tide Pool
Animal Planet states, “Unlike true crabs, hermit crabs have soft, vulnerable abdomens. For protection from predators, many hermit crabs seek out abandoned shells, usually snail shells. When a hermit crab finds one of the proper size, it pulls itself inside, leaving several legs and its head outside the shell. (A hermit crab has five pairs of legs, but not all of them are fully developed.) A hermit crab carries the shell wherever it goes. When it outgrows its shell, it switches to a larger one. Most adult hermit crabs are from 1/2 inch (13 mm) to 4 3/4 inches (121 mm) long. Living on the seashore, in tidepools, and on the sea bottom in deeper water, hermit crabs scavenge their food.”
Liam’s find is a hermit crab’s home!
According to a Marine Parks Western Australia webpage, the biggest threat to hermit crabs is people!
1) While beach goers are often searching for the most beautiful seashells to carry home, they might also accidentally collect the little shore critters who have carefully selected the same shells as their beachfront condos! One hermit crab’s home, in turn, unintentionally becomes a beachcomber’s “beach treasure.” Hermit crabs are amazingly good at hiding inside their shells to protect themselves from discovery. Before we put those seashells in our brightly colored plastic pails, we really should inspect each shell very carefully for signs of a resident hermit crab. When our 5 year old grandson, Liam, found an absolutely gorgeous moon snail shell on a beach near Galveston Island, TX, we didn’t see a little hermit crab inside. Then we did. Then we didn’t!! Hermit crabs are very clever and quite skillful at stealing themselves away in their homes.
2) It’s no surprise that the prized larger seashells are favored by shell collectors. This sometimes leaves slim pickings for growing, house hunting hermit crabs. *This is one very practical reason that beaches sometimes have collection limits for unoccupied seashells of 1 gallon, 5 gallons, etc. per person.*
3) Other hermit crabs are taken home deliberately to become pets. *It’s important to remember that live collection of shore life is prohibited on many beaches!* Marine Parks WA reminds us: “Hermit crabs make popular pets, but you should never ever take one from the wild. They should remain in its natural habitat to form an important part of the marine food chain and, if removed, are likely to die within days in any case.”
Alaskan Hermit Crab (Photo: Jan Haaga, PD-USGov-NOAA)
Related beachcombing posts: Tidepool Etiquette 101
Beachcombing? Shelling Regulations Abound. Know Before You Go!
Beachcombers Beware ~ Regulation Variation at National Seashores
Happy beachcombing to you and to our little ten-legged seashore friends!