Stroll along a Cape Cod beach in late August and summer is in full swing. Walk past the sun shelters and towels to the water’s edge. There, on an outgoing tide, is where to find the sea’s treasures.
That thin zone is home to a great many beach finds, especially after a storm has passed. One of the most interesting creatures is such a common sight, most pass it by without a second look. But the horseshoe crab demands our respect and support.
This ancient creature dates back 445 million years, compared to the dinosaurs arriving 240 million years ago. Not true crabs, they are arthropods, related to spiders and scorpions. Unlike their cousins, they don’t bite or sting. Their threatening looking tail is used to help right themselves when flipped over.
Their mating season is May and June when the larger females can be seen towing around a male in the shallow waters of the Cape. The crabs molt, shedding their exoskeletons, leaving a split in the front of the shell. These shells found at the tide line are often confused for dead crabs. Once the animal reaches maturity it stops molting, 9-11 years.
Their blood is blue and contains a clotting agent which is used to test for bacterial contamination in drugs. The animals are harvested and their blood collected before they are released back to the wild. A synthetic alternative to their blood now exists, which would help stop the harvest of the crabs which are already in a population decline because of habitat loss.
It is a wonder to think about an animal so old and unchanged, still prowling the shorelines of Cape Cod. In the last one hundred years, coastal development and advancing erosion have dramatically changed the view these creatures find when coming ashore. If you run across them on your beach wanderings, make a portrait of these “living fossils.”