The blood of the lowly horseshoe crab contains a chemical that can detect the smallest traces of bacteria in a test called LAL, which is short for Limulus Amebocyte Lysate. The blood test for bacterial contamination is big in the biotech business – drug developers depend on it, as do suppliers of surgical implants such as pacemakers and prosthetic devices. In fact, LAL from horseshoe crab blood can command $60,000 USD a gallon.
Horseshoe crabs live on the sea floor near the shore. When they want to mate, they swim into shallow water, and that's where they're nabbed. Processors pierce the tissue around the crab's heart and drain up to 30 percent of its blood. The crabs are then returned to the ocean 24 to 72 hours later.
Giving blood for mankind:
Well, if you lost 30% of your blood you'd be lethargic too. Just another incident of corporate greed. Why couldn't they be satisfied with 10 or 15%? Then maybe the crabs would feel more like mating.