Last week, we were going through blood and the circulatory system during Biology lessons. While I stared at the ceiling, unable to sleep yesterday night, I suddenly wondered how accurate the portrayal of vampires’ blood drinking habits are.
Okay, the basic rules and reasons for why vampires need to drink blood is because they are not alive, and, hence, are incapable of creating their own blood for themselves, right? So, discounting the fact that not being alive probably means that they wouldn’t need food or air or water, since they won’t be respiring, the red blood cells in the blood have the main function of transporting oxygen and carbon dioxide.
Since red blood cells have a life expectancy of 120 days, vampires only actually need to feed once every 120 days. And if their livers don’t function, they can actually last longer, even if the red blood cells won’t be as effective at their job as they were before the ‘expiry date’. So, that means that the symptom for ‘bloodlust’, where the vampires crave blood, would only be that they are extremely exhausted as they do not have enough oxygen or other nutrients to allow their body cells to respire and function.
Actually, doesn’t that make vampires normal humans who can’t produce their own blood?
Well anyway, the other big problem would be blood type.
A basic overview on blood type would be that your blood type is determined by the antigens present on the surface of your red blood cell, and the antibodies in your blood plasma. There are two types of antigens and two types of antibodies, and the combination of which antigen you have will determine your blood type.
Blood Type Antigen Antibody
. O N.A. A&B
. A A B
. B B A
. AB A&B N.A.
So, above is the chart of which blood type has which antigens and antibodies. A basic summary of what happens when you transfuse the wrong blood type: the antibodies present in the plasma of the person receiving the transfusion would bind to the antigen on the red blood cell of the blood they are receiving, causing the blood to clot, and, at the same time, the antibodies present in the blood being transfused would bind to the antigens on the blood in the person who is receiving to the transfusion, and the end result is a lot of blood clots that would kill the person because the blood vessels are all clogged up.
. O A B AB [Donor]
O || / / /
A || || / /
B || / || /
AB || || || ||
|| indicates that the blood won’t clot.
/ indicates that the blood would clot.
From the chart above, you can see that the AB blood type is the universal receiver, while the O blood type is the universal donor. Where’s the +/- ? Well, that I’ll leave out for this, we’ll just deal with the four main blood groups first.
Okay, now that we have all the pesky little knowledge needed out of the way, let’s go back to vampires. Actually, now that you know all this, can’t you see what the problem is? A vampire cannot simply go around biting people and taking their blood, because taking the wrong person’s blood will kill them. I’m thinking of the way this works as vampires basically receiving blood transfusions from normal people via biting them and swallowing their blood, so, much like during blood transfusions, if, say, vampire John Doe is of blood type A, and he got unlucky, chancing upon a victim that just so happened to be in the 3% of blood type AB running around the place, his blood would clot up and he would die.
So those stories where the vampires run around willy nilly and catch victims off the streets and just drink from them without checking their medicinal records? Well, the vampires are extremely, extremely lucky that everyone they’ve been drinking from has a blood type that won’t kill them.
Which brings us to another problem: vampires can’t produce their own blood. Thus, what would their blood type be? Well, my theory is that their original blood type would be dependent on either their blood type before they died, i.e. the blood survived the time during which they were dead, or it depends on the blood type of the first person they draw blood from.
But their blood type would change, since they cannot maintain the production of the blood cells and blood plasma to keep the blood type consistently whatever type it is. They depend on their prey for blood, after all, so wouldn’t the blood type simply change to become the blood type of the person whose blood they had last ingested?
In which case, they’d have to be constantly aware of their own blood type and use it to find the potential ‘donors’. And that just makes it so much of a hassle, being a vampire, doesn’t it?
And I’ll just stop here tonight, since, well.
Hope you had fun reading this!