Let’s Talk About Why Animal Blood Isn’t Red

Regardless of size, shape and habitat, blood is one of the most important components for organisms to live. The blood flow in the body delivers necessary gasses and nutrients to organs and carries out waste products to be excluded from the body. But, despite our assumptions, all blood is not red. Blood can contain several different components responsible for giving it different hues. From milky blue to lime green, we can find a rainbow of shades in blood depending on the species. Let’s look at some reasons that give blood a different color.

Varied Internal Components

According to a marine biologist from Stanford University, Stephen Palumbi, some crabs, squids, octopuses, and crustaceans have blue blood. Their blood contains copper-enriched hemocyanin, which is typically colorless, but turns blue while binding with oxygen. According to Palumbi, hemocyanin is a vessel to move oxygen around, just like the hemoglobin in the human body. Hemerythrin is another iron-containing pigment that can be found in some mollusks like Sea Squirts and Lamp Shells. After being attached to oxygen molecules, it gives a purple-pink shade to the blood of these marine animals. Insects possess a blood-like fluid named hemolymph, which contains bluish-green or yellowish pigments. Here, the color comes from the plant diets of the insects.

Blood Used as Weaponry

The Green Tea Skinks of New Guinea have a lime green-colored body and similarly green-colored blood! The director of the Louisiana State University Museum of Natural Science, Chris Austin, discovered the component biliverdin as the prime cause of turning the reptile’s blood, mouths, bones, tongues, and other body parts bright lime green. Biliverdin is a bile pigment, which is the waste-product of broken-down red blood cells. Constant buildup of these dirty blood pigments is a defense strategy of the reptiles to kill off blood parasites. Reptiles and insects like the US horned lizards, Asian lady beetles, etc., can also use their blood or a blood-like stinky fluid as a defense mechanism.