During my first year of grad school I conducted a jailbreak– a fellow grad student and I snuck into the Invertebrate Zoology lab and freed all the horseshoe crabs. I wish we’d know then that we dropped about $50,000 back into the sea. Of course, horseshoe crabs aren’t that expensive, but their blood is. One quart of horseshoe crab blood costs around fifteen thousand dollars . And why would anyone pay for that? Well, in addition to coming in a shade of oh-so-chic blue, it also saves human lives.
Horseshoe crab’s superpower blue blood is a bacteria killing machine, and scientists are literally borrowing this trick to help test medical injections for contamination. When a horseshoe crab is cut, the wound is immediately slathered in bacteria from its murky surroundings. To prevent a potentially lethal infection, certain blood cells carry compounds that cause the blood to clot up when exposed to bacteria fragments. Cut. Clot. Cut. Clot. The horseshoe crab is quickly sealed back up and ready to go. There it is, our horseshoe crab wallowing in a muddy pit, fighting infection and being awesome.