So, it kind of concerns me how some people think blood works, so I decided a little information and speculation in regards to trolls was necessary.
Why is Human blood red?
Contrary to some people’s beliefs, human blood is not red because of pigments in the blood, nor is it actually blue or any other color within your veins and arteries.
Human blood is red because red blood cells are red. Red blood cells are red because within these cells, there are proteins call Hemoglobin. Hemoglobin has subunits called Hemes, which contains the element Iron. This iron interacts with the oxygen that comes into the bloodstream through our lungs and breathing, is oxidized, and therefore appears red due to how the chemical bonds between iron and oxygen reflect light.
When oxidized, our blood looks bright red (what you typically think the color of blood looks like – since it becomes oxidized when it makes contact with the air outside the body). When it is not oxidized/in contact with oxygen, it is dark red (I believe it is quite close to the color of our beloved troll rustbloods).
Human blood is never blue or green. The only reason blood looks blue or green when you can see your cardiovascular system through your skin is because of the way it alters the reflection of light.
What other blood colors are present on Earth (in other animals)?
1. Spiders and certain species of arthopods have blue blood – this is due to the presence of copper-based hemocyanin in their blood. It is also based on oxygen transportation within the blood and is therefore blue due to the oxygen-copper interactions in the blood.
2. Insects don’t breathe like most vertebrates do – I believe they breathe through their skin (?) – and therefore don’t really need the same oxygen carrying abilities in their blood [Note: Trolls, while insect based, probably do not breathe through their skin, and would still need oxygen or some other elemental bonding protein to carrying this gas through their bodies.].
a. They therefore often have yellow blood. This is due to a high concentration of vanabin, which contains vanadium. Vanadium oxide is yellow. Nobody is quite sure what this vanabin does, as it doesn’t carry oxygen like hemoglobin or hemocyanin does.
3. There is a type of skink that has green blood, due to a buildup of bile that has a pigment called biliverden. This buildup probably makes them toxic to eat, and therefore functions as a type of protection.
a. Humans have very, very trace amounts of bile like this in their blood, which only really appears during bruising, causing the yellowish-greenish color while the bruise heals. It would only affect blood color in extremely high concentrations, and would kill a human. Some people think that the skinks possibly had an evolutionary mutation at one point which allowed them to survive with high traces of bile in their blood.
b. Note: Bile is a waste product of the breakdown of the heme moiety of hemoglobin in erythrocytes. Trolls probably have similar molecular breakdowns and such, as their biology in many respects does not appear too different from our own.
Sulfhemoglobinemia is a rare condition in which there is excess sulfhemoglobin (SulfHb) in the blood. This causes it to have a slight greenish color and causes cyanosis. It also results in an inability to carrying oxygen as needed in many cases.
It is also due to environmental and chemical concerns, not due to genetic concerns.
What color would blood be without the presence of these proteins and such?
Most likely kind of clear, or like with polar bear fur, appear kind of white with the reflection of light. What does this mean? White blooded trolls are incredibly, incredibly unlikely to exist for the reason that if you don’t have any of these things in your blood (or whatever trolls have in their blood), you would die. Like, this is a pretty severe “mutation” if it could happen biologically. You would be seriously fucked up. You wouldn’t survive even to become a living grub, most likely, or die upon your first “breath.”
Not Completely Unlikely (Though Not Necessarily True) Biological Headcanons For Troll Blood Colors:
1. Candy red and burgundy bloods have blood compositions almost exactly like our own – with only very slight differences, perhaps, in the volume of red blood cells, or perhaps in the barest composition of their oxygen carrying proteins.
2. Highbloods (blue bloods in particular) possibly have things like the Hemocyanin, which would make sense giving their closeness to being seadwellers and the type of animals that have blue blood on Earth (Hello, spiders and Vriska!).
3. Midbloods could have higher concentrations of bile, much like the skinks! Midbloods, on average, do not have the strength of the highbloods and such, nor the psychic abilities of the lowbloods. A good protective measure against not only other trolls, but especially large beasts who might want to eat them, would be toxic blood, or at least blood that would make them taste nasty as fuck.
a. By “toxic” though, I don’t mean to imply that they’d have acid blood that would burn at the touch or something. It’s mostly a taste/consumption thing to drive away predators. Try not to nom on any midbloods, guys.
4. The presence of other types of proteins that could carry other types of gases, if trolls (possibly seadwellers), do not require oxygen, but some other gas (I’m not quite sure if this would work, however, it’s just a speculation and an unlikely one). The gas composition of the troll’s planet is very, very likely to be like that of Earth – considering that humans and trolls survive together in the same place without any difficulties mentioned.
>>>> EDIT: Upon doing a little extra research, I find this possibility even more unlikely, as the only other gas extremely prevalent in our atmosphere (enough so to breathe) is Nitrogen, which is far, far less reactive than oxygen, and is far more lacking in chemical energy compared to oxygen. For complex organisms such as humans (and probably trolls), the energy required to break apart Nitrogen molecule bonds to use the energy inside of those bonds would be FAR higher than the energy outcome.
Even those "nitrogen-fixing" organisms (usually unicellular), usually exist in a symbiotic relationship with another organism: "I will supply your nitrogen requirements from atmospheric nitrogen gas if you will provide for my energy needs for that chemistry, and for my own continued existence and reproduction."
>> Basically what I'm saying is that breathing a gas other than oxygen is either not realistic (Nitrogen), makes you more of a plant than an animal (Carbon Dioxide), or are not prevalent enough in the air to breathe (Argon and other trace elements in the air).
a. Sburb is also a repeating process, so the game likely uses the same amino acids and genes to create trolls as it does humans, just with slightly different genetic combinations to make them.
In case you guys didn’t know, albinism only affects the pigments of your skin, not the elemental composition of your blood. Albinism + blood color change = 2 mutations at once. Even if you headcanon that troll blood does have pigments of some sort, it’s still two different mutations to have albinism (which affects the skin) and a mutation that changes the color of the pigment of the blood.
Not too hard there.
NOTE: Anything regarding trolls in here are headcanons, just like any other headcanon anyone else has about the same topics. Believe what you want. XD