An enzyme in the blue blood has been key to testing vaccines since the 1980s, raising concerns for the crabs’ population. But regulatory approval and new data are signaling the tide may be turning orseshoe crabs evolved 445 million years ago and have been around for 1,500 times longer than Homo sapiens. It was not until the 20th century, however, that scientists discovered life-saving properties in their blood. Todd Rosenberg / Eli Lilly and Company ========================================================== Each May, hundreds of thousands of horseshoe crabs climb onto beaches along the eastern coast of the United States. An invertebrate’s “Love Island,” males...