A planet that has 56% nitrogen, 40% oxygen, and 3% sulfuric dioxide has life on it. The most efficient color of blood on Earth is red iron based blood. What would be the most efficient pigment for their blood?


closed as unclear what you're asking by Mołot, sphennings, Azuaron, MozerShmozer, Aify May 1 '17 at 21:33

Please clarify your specific problem or add additional details to highlight exactly what you need. As it's currently written, it’s hard to tell exactly what you're asking. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

  • 1
    $\begingroup$ At 40%, oxygen would be a pretty potent oxidizer. $\endgroup$ – a CVn May 1 '17 at 17:35
  • 4
    $\begingroup$ Arget, please avoid editing to change what you are asking. (It's always annoying to have the question change under your feet.) You would be better off deciding what you want to know, researching that a bit, then ask about whatever you fail to grasp, while showing that you have tried yourself before asking for help. Also, now that you have earned a bit of reputation from your previous question, you may want to try the question sandbox on Worldbuilding Meta where many issues can be worked out before you post the question on the main site. $\endgroup$ – a CVn May 1 '17 at 17:45
  • 2
    $\begingroup$ Okay, so now we've gone from oxidizer, through changing from sulfur to sulfur dioxide in the atmosphere, to a "base" for blood, to a pigment. What's next? I think this is starting to qualify as a chameleon question. $\endgroup$ – a CVn May 1 '17 at 17:49
  • 3
    $\begingroup$ There's no real reason (AFAIK) to think that red is the "most efficient" color of blood - that's not how evolution works. Rather, some ancestor of the vertebrates developed hemoglobin-based blood, and it was good enough to do the job so it was conserved. A different random evolutionary twist, and we might have had blue blood, or clear, like some invertebrates. Or someone with extensive knowledge of biochemistry might design a more efficient blood that is green or purple... $\endgroup$ – jamesqf May 1 '17 at 18:05
  • 4
    $\begingroup$ @Mołot I know it technically isn't a chameleon question until it keeps changing in response to answers, but such repeat changes as we have already seen on this one makes at least me unwilling to take the time to research and write an answer. At the very least, it hints that the OP doesn't really know themselves what they want to know. $\endgroup$ – a CVn May 1 '17 at 18:25

Blood is red because of the way iron and oxygen interact in the hemoglobin, not because of pigment. To know what colour the blood should be, you'd have to design your own hemoglobin equivalent to fit that environment and work out what colour it would be. That's a lot of work, but if you want to do it, more power to you


Not the answer you're looking for? Browse other questions tagged or ask your own question.