The mystery of lime-green lizard blood. Green blood is one of the most unusual characteristics in the animal kingdom, but it's the hallmark of a group of lizards in New Guinea. The muscles, bones and tongues of these lizards appear bright, lime-green due to high levels of biliverdin, or a green bile pigment, which is toxic and causes jaundice. Surprisingly, these lizards remain healthy with levels of green bile that are 40 times higher than the lethal concentration in humans. Source 1w.