Horseshoe crabs have resilient immune systems; they do not have adaptive immune systems like humans that have to "learn" how to defend from a new pathogen. Inst

Horseshoe crabs have resilient immune systems; they do not have adaptive immune systems like humans that have to "learn" how to defend from a new pathogen. Instead, their immune systems are general purpose. This is exactly why their blood is valuable for testing for the presence of pathogens in drug and device testing.