[Lee Stewart]

In the 1960s, scientists discovered that horseshoe crab blood could be used to detect even the smallest amounts of harmful bacteria. Since then, the pharmaceutical industry has been using it to make sure our injections, vaccines and surgical implants are all free from contamination.

And so, every year along the U.S. East Coast, 500,000 crabs are collected, cleaned, measured and then drained of as much as one-third of their copper-based, baby-blue blood. Collections also take place across the eastern shores of Mexico and China. Demand for the blood is high—it’s been called blue gold and is reportedly worth up to $60,000 a gallon.