Horseshoe crab are marine arthropods of the family Limulidae and order Xiphosura or Xiphosurida that live primarily in and around shallow ocean waters on soft sandy or muddy bottoms. They occasionally come onto shore to mate.
Unlike vertebrates, Horseshoe crabs have bright blue blood. Isn’t it weird?
In fact, as our blood does, their blood kind of sloshes around in their bodies carrying oxygen to various organs.
Our blood is red because we use hemoglobin to move oxygen around. Hemoglobin has iron in it, which gives off a reddish hue. (Think of rust.) Horseshoe crabs use a copper-based molecule called hemocyanin to distribute oxygen. In nature, copper turns things blue or blue-green. So that’s why their blood is blue; it’s copper-based.
Besides being blue, 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.
in fact, the Horseshoe bleu blood clots when it comes into contact with foreign bacteria. In other words, this stuff’s ideal for detecting impurities. And humans use it to do just that, in products like pharmaceutical drugs. If the cells clot, that means those products have been contaminated by “negative” bacteria, a very useful alarm system. All of a sudden, horseshoe crab blood became valuable (one quart is worth more than $10,000).
Without killing the crabs, Scientists were able to get some of the valuable bleu blood. They hook up the crabs to vampire machines, take what they want, and return the crabs to the bay. Most survive the process.
Biologist Carl Shuster, worried a little bit about the 3 to 15 percent of crabs that don’t survive their ordeal on The Machine. He talked the government into creating a horseshoe crab preserve, where crabs can live free of fear of the red-blooded, white-faced monsters that grab them from their homes and suck out their blood.