Limulus polyphemus

Atlantic Horseshoe Crab


Welcome to Horseshoe Crab Biology!

Above is a picture of an Atlantic horseshoe crab.

Welcome to the realm of the Limulus polyphemus!  In this website you will explore the intriguing world of the Atlantic horseshoe crab.  This animal has the shape of a horseshoe giving this organism its common name.  An adult horseshoe crab is brown with a long skinny pointed tail as seen in the photo above. Underneath the hard exoskeleton shell there is a completely different appearance.  The horseshoe crab has has six appendages, a pair of chelicera, ten legs, six book gills, and averages 7" by 12" in size.  The horseshoe crab is often mistaken to be related to other crabs because of its common name.  The truth is, this organism is more closely related to spiders, mites, and scorpions! To learn more about two different species of spiders that the horseshoe crab is related to, click here for the zebra spider and click here to view the Gasteracantha cacriformis. To explore more about a species of scorpion like the water scorpion, click here.  Uncovering the amazing life of the Limulus polyphemus is just a few clicks away!


To learn more about the classification of the horseshoe crab click here!

Want to learn about other fascinating organisms?  Visit