FAR FROM CRABBY: HORSESHOE CRABS, HERMIT CRABS, AND GHOST CRABS
Hilton Head Island is a natural habitat for eleven different crabs and a few marine animals that share the crab’s name. Each refreshing walk on the beach brings discoveries that are fascinating to observe. Horseshoe crabs, hermit crabs, and ghost crabs happily reside along the shoreline, yet the only thing they have in common is their name and address.
This ancient marine animal looks frightening but is harmless. The firm tail, called a telson, is not used for defense; its telson can flip it over or help with stability. Your nose will let you know if the horseshoe is deceased or if it is an empty shell. A juvenile will molt its outer shell, the exoskeleton, 15-16 times until it reaches its adult size at around ten years old.
The underside of the horseshoe crab reveals seven pairs of legs that uncover the truth that it is not a crab but closer to an arachnid, spider classification. Check out the seven sets of legs that almost resemble a scorpion. Only the female has a giant pincher claw near her mouth. The unique book gills and flat mouth are also easy to spot and fascinating to see.
With simple eyes and compound eyes, plus light sensors near the telson, extraordinary vision guides the horseshoe crab. Two eyes are exclusively programmed for spotting mates, bringing new meaning to the phrase, “I only have eyes for you!” Horseshoe crabs often travel to the shallow shoreline to mate in late spring.
If the pretty shell you pick up on beach walk suddenly wiggles, and you see two little eyes shyly peeking out, then you discovered a hermit crab. They are not crabs since they hatch from eggs as zoeae and are without a shell. They are little hermits that scavenge discarded mollusks or whelk shells to shelter in and protect their soft abdomen.
Hermit crabs have dedicated house hunters as they constantly outgrow their shells. They are communal critters yet will aggressively fight over a prized shell! (Maybe they need a good realtor!) They clean up the beaches eating algae and bits of fish, worms, and plankton.
Take time to observe these fascinating hermit crabs dragging their different shaped homes behind them, but don’t attempt to take them home. Aquatic hermit crabs need saltwater to survive, and local pet stores sell land crabs as pets. Their extra-large gills absorb the oxygen from the water, which is 1% only oxygen instead of 21% oxygen in the air. Their gills retain water, so the crab’s intertidal lifestyle lets them stay on dry land for up to 12 hours, yet they will burrow to remain moist.
What was that? A glance may be all you see of a ghost crab as it hurries over the sand! Grab some LED turtle-safe flashlights and friends and treasure hunt the night away at the beaches of Port Royal, Folly Field, Sea Pines, Palmetto Dunes, or any of Hilton Head’s stunning beaches! Of course, the real win is in finding the ghost crabs, not touching or catching them!
The ghost crabs are named after their quick movements. Their four sets of legs and two claws can scurry sideways up to 10 mph. Therefore their scientific name is ocypodes, which means fast feet. Bobble eyes may have been a better name as their roaming eyes can spin a full circle!
Hilton Head’s damp shoreline and warm climate are ideal living conditions for the ghost crab to keep its gills moist and breathe the fresh air. The random holes located around the beach house the ghost crabs out of the direct sun. The angled slope allows a breeze to cool their tunnel, reaching almost four feet in depth. Clams, insects, turtle eggs, and turtle hatchlings are the ghost crab’s favorite foods.
Happy memories- not crabby ones - fill Hilton Head’s spectacular shore along with a collection of priceless sea life! Understanding the valuable and unique features of the horseshoe crab, hermit crab, and ghost crab enhance our life on this well-preserved island!
Contributed by Janice MagninPosted by Christina Galbreath-Gonzalez on