Limulus polyphemus

Atlantic Horseshoe Crab


Can I Get an Order of Bivalves with a Side of Clams?

What Do I Eat?

 Horseshoe crabs have a wide range of food resources.  As said before, horseshoe crabs are secondary consumers.  They mainly consume a wide variety of mollusks.  They feed upon many species of bivalves and lots of different clams.  Clams include the surf clam, macoma clam, blue mussel, wedge clam, razor clam, fragile razor clam, and soft-shelled clams.  They also eat different kinds of worms. Not only do they consume animals, vascular plant material has often been found in sampled horseshoe crabs.


Above: Blue Mussel
Below: Surf Clam

How Do I Eat?

To obtain its food, the horseshoe crab will dig after the organisms in the sand.  Once it gets a hold of its organism of choice, it will grab it and crush the food with its chelicerae.  It then it push it into the mouth. 

Circulatory System  

Horseshoe crabs, like the other arthropods, have an open circulatory system.  The oxygen taken in from the book gills is then transported through the open circulatory system.  The heart is a tubular heart which extends the length of its body and beats very slowly compared to humans.  The heart is a ver y muscular region on the dorsal side of the organism and is slightly outlined on the exoskeleton.  The horseshoe crab's hemolymph has hemocytes in it.  Hemolymph is their "blood" and hemocytes are responsible for the organism's defense. The hemolymph is the fluid that transports nutrients within the open circulatory system while hemocyanin is the oxygen carrier.  The dungeness crab also has an open circulatory system, to uncover more information about them click here!

Above: Shells from the bivalve species, Atlantic rangia - Rangia cuneata


If you would like to learn about the reproduction of the horseshoe crab click here!

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