Scientists Say These Toxic Green-Blooded Lizards Could Show Us How to Save Lives
If you thought the acidic, greenish-yellow xenomorph blood from Alien seemed far-fetched, then consider that there are skinks in New Guinea whose green blood is so packed with toxic chemicals that it would be enough to kill a human.
To be clear: this isn't a kind of poison the skinks secrete from their skin as a dense mechanism, this is their blood.
Not only can these skinks survive the incredibly high levels of toxicity, there are multiple species of these green-blooded skinks running around New Guinea, suggesting that there's some evolutionary advantage to it.
The chemical that makes this blood so toxic is biliverdin, a greenish pigment formed as a waste product from the processes normal blood goes through.
If you've ever seen a greenish tint to a bruise, biliverdin is the culprit. It's also the precursor to bilirubin, a substance that causes a yellowish tint to the skin, especially in jaundice.
Both bilirubin and biliverdin are relatively safe in small quantities but can cause sickness if they begin to build up within the body.
The fact that several species of New Guinea skinks seem to thrive on having these breakdown products in their blood is fascinating to scientists like Zachary Rodriguez, one of the authors of a new study exploring these animals: "In addition to having the highest concentration of biliverdin recorded for any animal, these lizards have somehow evolved a resistance to bile pigment toxicity."
Rodriguez is part of a team that went into New Guinea to take samples from 52 skink species, including six that had green blood. By examining the DNA of the skinks, they found at least four different lineages of green-blooded skinks and that each one evolved separately from predecessors with normal red blood. This seems to suggest that skinks developed toxic green blood (and resistance to it) several times, rather than being an evolutionary oddity.
Using their knowledge of these lizards, Rodriguez and his team hope to identify new ways to treat humans suffering from malaria and jaundice.
One last fun fact about these weird little lizards: all that biliverdin in their blood makes not only their skin green; it makes their tongues (and muscles...and bones) lime green, too. Fabulous.