Every year, more than 400,000 crabs are bled for the miraculous medical substance that flows through their bodies—now pharmaceutical companies are finally committing to an alternative that doesn’t harm animals. Unlike human red blood, the blood of the horseshoe crab is in milky blue. This is because as oxygen is transported by hemocyanin instead of haemoglobin in vertebrate. That is the reason which makes it valuable. The blood of horseshoe crabs is harvested on a massive scale in order to retrieve a cell critical to medical research. However, recent innovations might make this practice obsolete. Horseshoe crabs’ blue blood is so valuable that a quart of it can be sold for $15,000. This is because it contains a molecule that is crucial to the medical research community. Horseshoe crabs are sometimes called “living fossils” because they have been around in some form for more than 450 million years. In this time, the Earth has gone through multiple major ice ages, a Great Dying, the formation and subsequent breaking up of Pangaea, and an asteroid impact that killed the dinosaurs and most of life on Earth yet again. In other words, horseshoe crabs have truly seen some shit. In the United State, all drugs approved by the Food and Drug Administration (FDA) have to be tested for bacterial contaminants. Endotoxin is a common bacterial contaminant in drugs which might lead to toxic shock or life-threatening fever if it is injected into our body. Fortunately for horseshoe crabs, this practice may be dying out. Researchers discovered that a molecule in LAL called factor C was responsible for its clotting action. Researchers genetically modified the guts of insects—who belong to the same phylum as horseshoe crabs, Arthropoda—to produce factor C. As a result, the insects began pumping out factor C, which could then be sold as recombinant factor C (rFC) on the market as a viable substitute to horseshoe crab blood. Though rFC has been on the market since 2003, it’s been slow to gain traction. Initially, it was only being produced by one manufacturer, the Lonza Group. Pharmaceutical companies are wary to rely on a single manufacturer in case an emergency occurs, and their supply is cut off. The Food and Drug Administration’s (FDA’s) regulatory process was quite slow as well. But these obstacles are gradually being overcome. Hyglos GmbH, another pharmaceutical manufacturer, began producing rFC in 2013. European regulatory bodies have approved its use, which lays the groundwork for future approval by the FDA. Major pharmaceutical companies who have used rFC have confirmed that it works just as well as LAL. Today, experts believe that rFC will become the dominant method of detecting endotoxins, letting horseshoe crabs off the hook.