I was in Assateague, Virginia, some weeks back, doing the summer beach thing. The wild horses, standing hoof-deep in the chilly saltwash, were lovely, as they always are. They’re one of the truly special things about this national seashore. The horseshoe crabs? Lovely in their own way, I suppose, and definitely special. Especially this one, with its crustacean backpack. The host was deceased, unfortunately, but its riders were still with us, holding on tight.
I knew a few things about horseshoe crabs before spotting this one, including that they’ve been around for more than 400 million years, that they haven’t changed much in that time, and that their blood–which happens to be blue because of a copper-based respiratory pigment called hemocyanin–is used in human medicine. Why/how that last bit? I looked up the details: Scientists discovered a protein in the crab’s blood called limulus amebocyte lysate that clots when it come into contact with endotoxins (toxic bacteria). So the substance can be used as a toxin-detection system that helps ensure vaccines, drugs, and medical devices aren’t contaminated before they’re put inside people.
Now, the bad part. Hundreds of thousands of crabs a year are bled for this purpose, the animals strapped down in a sort of gruesome assembly line, their aqua-blue lifeblood draining into clear bottles. This upsets me. Even with a synthetic alternative available (and used in Europe), the practice of using wild animals continues in the good ole’ U.S. of A. Supposedly the animals can be released, unharmed, after being bled, but many, many still die during what must be a stressful procedure, or even during capture or when moving them place to place. (Some people involved of course aim to be humane, but it’s just not a crab-considerate process. Period.)
On a happier note, the horses! Plus, horseshoe crabs have 10 eyes. How about that! This site has a good horseshoe crab anatomy lesson, if you’re interested.
That’s it for now.
[Photos by the author.]