28 Jun A Living Fossil?!

Horseshoe crabs are lining up on the ocean as we speak! Do you know why? June is horseshoe crab mating season. They enjoy coming out at night so they can mate and lay their eggs. Just the other night, I was walking down the bay and got to see about a hundred horseshoe crabs lining up along the shoreline.

It was an especially crowded night because of the full moon. As I walked along the shore, it was interesting to see them pairing up in doubles, triples, and even quadruples. I also got to pick up a lone horseshoe crab, place it on the sand, and see it turn itself over with its tail. However, horseshoe crabs don’t only come out at night. On the Father’s Day breach hike, the rangers and I got to see multiple pairs of horseshoe crabs mating at the breach that connects the Atlantic Ocean and Great South Bay.  I wonder why they liked it there? I’ve learned a lot of interesting facts about horseshoe crabs while I’ve been here. One fact is that they are nicknamed “living fossils.” They acquired this odd nickname because their anatomy hasn’t changed for the past 445 million years. Another interesting fact about this marine arthropod is that they’ve been saving the lives of millions of people since the 1970s. Their blood is useful towards testing vaccines and sterilizing medical equipment. Unlike our red and iron-based blood, theirs is blue and copper-based. Horseshoe crab blood allows for a high functioning immune system. It works well because when their blood encounters a pathogen, the blood quickly clots around it. Therefore, their blood is useful in identifying if a vaccine has the potential to be harmful. Before this discovery, scientists would test vaccines on rabbits. Scientists would inject the rabbits with the vaccine and then observe if the rabbit would die, get sick, or stay healthy. Therefore, rabbits are also very thankful for horseshoe crabs. Horseshoe crabs are a very interesting species and are often overlooked. I hope to teach more visitors at Fire Island about this cool species.