If you have ever taken medication, received a vaccine, or had a surgical implant, you should thank a horseshoe crab. These prehistoric-looking animals are actually really important to modern medicine. But why?
It’s all about their blue blood. Mammals have hemoglobin in their blood, which contains iron- hence the red color. But horseshoe crabs transport oxygen through their bodies via hemocyanin, which contains copper, making their blood blue.
Even more interesting is a compound in the crab’s blood called Limulus Amebocyte Lysate, or LAL. LAL binds to bacteria, viruses and fungi and acts to protect the animal’s system from infection. It’s worked pretty well- horseshoe crabs have been around since about 100 million years BEFORE the dinosaurs, and they’re still going strong!
This ability to bind endotoxins makes horseshoe crab blood incredibly useful- and valuable. LAL is the worldwide standard screening test for bacterial contamination, and it’s used to test drugs, vaccines and surgical implants. LAL can detect endotoxins as low as .1 parts per trillion!
The best part is that harvesting horseshoe crab blood doesn’t require the animals to be killed! The crabs are caught, blood is drawn, and they are put back into their environments, where their blood volume is replenished within about a week. Watch this video to see how it’s done, and read more about it here: