myfrogcroaked:

“Animal blood comes in a rainbow of hues because of the varying chemistry of the molecules it uses to carry oxygen. Humans use hemoglobin, whose iron content imparts a crimson color to our red blood cells. Octopuses, lobsters, and horseshoe crabs use hemocyanin, which has copper instead of iron, and is blue instead of red—that’s why these creatures bleed blue. Other related molecules are responsible for the violet blood of some marine worms, and the green blood of leeches. But the green-blooded lizards use good old hemoglobin. Their red blood cells are, well, red. Their green has a stranger origin: Biliverdin.

They should be dead. Biliverdin can damage DNA, kill cells, and destroy neurons. And yet, the lizards have the highest levels of biliverdin ever seen in an animal. Their blood contains up to 20 times more of it than the highest concentration ever recorded in a human—an amount that proved to be fatal. And yet, not only are the lizards still alive, they’re not even jaundiced. How do they tolerate the chemical? Why did they evolve such high levels of biliverdin in the first place? And why, as Austin’s colleague Zachary Rodriguez has just discovered, did they do so on several occasions?”

Source: TheAtlantic

These Lizards Are Full of Green Blood That Should Kill Them