This is a horseshoe crab. A horseshoe crab’s bright blue blood is used to test vaccines, drugs and medical devices to ensure that they aren’t contaminated with dangerous bacterial toxins
Horseshoe crabs have been around even before the dinosaurs. However, conservationists fear that this 450-million-year-old living fossil may soon be pushed to the brink of extinction
A horseshoe crab’s blood contains a special clotting agent limulus amebocyte lysate (LAL) which detects a contaminant called endotoxin. If even tiny amounts of endotoxin make their way into vaccines or injectable drugs, the results can be deadly.
Therefore, it has been essential for testing the safety of biomedical products since the 1970s, when it replaced rabbit testing.
Every year, pharmaceutical companies round up half a million Atlantic horseshoe crabs, bleed them, and return them to the ocean after which many will die.