Horseshoe crab

Natalie Richards

field guide

November 6, 2015

Horseshoe crab

The horseshoe crab, Limulus polyphemus, are most commonly seen in spring and summer months. Juveniles live in shallow water in the southern New England area, while adults live in the deeper waters, also in the southern New England area, which is in the United States. The horseshoe crab is a heterotroph, meaning it doesn’t produce it’s own food. It is also ectothermic, meaning it’s cold-blooded and it’s body temperature relies on it’s surroundings. Also, the horseshoe crab has biradial symmetry. Many types of shorebirds eat horseshoe crab eggs. Various fish, invertebrates and sea turtles feed on eggs and larvae. Humans catch adult horseshoe crabs to use as bait and for medical research. It eats worms and mollusks such as soft-shell clams and razor clams. An interesting fact about the horseshoe crab is that they aren’t true crabs. They are more closely related to terrestrial spiders than blue crabs. Another fact about the horseshoe crab is that its ancestors date back over 450 million years-long before the age of the dinosaurs. The order of classification is that the domain is eukaryote, and the kingdom is animalia. Next, the phylum is arthropoda, and the class is merostomata. Also, the order is xiphosura, and the family is limulidae. Lastly, the genus is Limulus, and the species is polyphemus. A structural adaptation is that the horseshoe crab has a very hard carapace that protects its body from predators or harmful objects, such as hard debris. A functional adaptation is that its long tail helps it flip back over, if flipped over. Lastly, a behavioral adaptation is that the horseshoe crab buries its eggs, which makes it much less likely for its eggs to not survive, because it’s buried in deep into the sand. Horseshoe crabs grow to two feet in length. They have a hard, rounded, brownish-green exoskeleton, a spike-like tail and five pairs of jointed legs. Their widely spaced eyes look like bumps on the top of their shell. Their gills have folds of membranes that look like the leaves of a book. Juveniles are sand-colored. Thats all about the horseshoe crab! (I never held the horseshoe crab, so I choose a pic

of Jane!)