what color is a horseshoe crabs blood
A horseshoe crab has blue blood which is copper based instead of iron based like our blood (thatâs why itâs blue instead of red). This blood has another unique quality, horseshoe crabs blood will gel when it comes in contact with bacteria or endotoxins. This action is part of the horseshoe crabs primitive immune system. If a horseshoe crab sustains an injury such as a cut, when bacteria tries to enter itâs body, itâs blood jells which creates a barrier against the bacteria.