Some
invertebrates have
blue blood, too - literally.
Oxygen is carried in their blood by a chemical called
hemocyanin, similar to the familiar
hemoglobin that reddens the blood of
vertebrates but containing
copper instead of
iron.
The best-known example of a blue-blooded animal is the lobster, which is often consumed by aristocratic "blue blooded" humans, giving a bit of credence to the adage "you are what you eat." Others include the horseshoe crab, crayfish, scorpion, octopus, squid, clam and mussel.