I just discovered one of my friend is an android! That's a big shock, as she looks, acts, reacts, eats and drinks like a human. She didn't even know herself she wasn't human.

While I partly understand how her unnatural body functions, there are still some black spots.

My android friend bled.

How is it possible?

After scratching my head I came with two options:

  • There is some kind of "blood reserve" in her body;
  • Some mechanism is transforming what she eats and drinks into blood-like substance.

I do suspect the second option, but I don't know how it can be done.

How can nutrition consumed by an android produce blood-like substance?

Or is there something else that produce this blood?

"Blood-like substance" mean the following:

  • It looks like blood but I wasn't close enough to her to see if it was exactly like blood;
  • Smell and taste may be not like blood.

Of course I don't know her creator so I can't ask them myself nor can I dissect the android... After all, she's still my friend.

  • $\begingroup$ Welcome to worldbuilding, when you have time make yourself familiar with this site by taking the tour and visiting the help center. $\endgroup$
    – L.Dutch
    Aug 9, 2018 at 15:42
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    $\begingroup$ What is your definition of "android?" How artificial is your friend? I'm assuming if she appears in every way like a human, to the point that she bleeds when cut, she has at least some organic matter. If by android you simply mean she was designed and built by someone and is driven by an AI instead of a human brain, you could go so far as to make her an anatomically correct human with a computer in her skull instead of a brain. $\endgroup$
    – Zenon
    Aug 9, 2018 at 15:48
  • $\begingroup$ Welcome to Worldbuilding, Thyerus! If you have a moment, please take the tour and visit the help center to learn more about the site. You may also find Worldbuilding Meta and The Sandbox (both of which require 5 rep to post on) useful. Here is a meta post on the culture and style of Worldbuilding.SE, just to help you understand our scope and methods, and how we do things here. Have fun! $\endgroup$
    – Gryphon
    Aug 9, 2018 at 15:51
  • $\begingroup$ @Zenon She looks like a human but is totally artificial, from skin to brain. She bleeds when cut and somehow repare herself (still thinking about this part) artificially. $\endgroup$
    – Thyerus
    Aug 9, 2018 at 15:55
  • $\begingroup$ @Thyerus I think you need to be more descriptive about your creature if you want to get answers that work with your world. What materials are we looking at here? How advanced is the technology her creator had access to? If you're giving us microscopic robots, anything can happen. $\endgroup$
    – Zenon
    Aug 9, 2018 at 16:00

2 Answers 2


Answering the title question before the edit

Since no one noticed before, that means her wounds heal like a normal human. How does fake skin heals? Nanobots of course! They float around in a blood-red plasma-like lubricant (some clear low-viscosity oil) to quickly move around the body. They extract carbon and other materials from the food, closely mimicking the needs of a normal human.

Answering the question in the post

That's an easy one. It's rust, suspended in the plasma-like lubricant. Your friend's insides are partly made of iron and like engines, friction always scraps off some molecules of iron off the surface. You friend breath. Iron + oxygen = rust. Blood tastes metallic to most people, this wouldn't be very different.

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    $\begingroup$ Damn, you beat me there... to add, Human, blood carries not only oxygen around but also everything needed to repair damage, the blood colour and taste is usually due to high iron content, which may or probably is an important repair material, like in real humans, and the nanobots take the useful materials out of the "blood" that they need in order to repair damage. $\endgroup$ Aug 9, 2018 at 15:58
  • $\begingroup$ Nanomachines, son! Memes aside, the rust idea is clever because iron oxide can be used as a pigment to mimic blood. $\endgroup$
    – Hawker65
    Aug 9, 2018 at 16:09

I would choose the second option and say that the fluid is produced by the android as a lubricant int the joints and muscles and or/as a source of fluid to emulate the bodily functions (sweat for example).

After the food she eats is "digested" in the stomach some parts could be turned into said liquid by an extra organ which passes the liquid onto the heart (enabling the android to simulate a heartbeat). The heart could also act to filter any foreign objects out of the fluid.

The fluid could consist of water, salt (for sweat), something oil like (maybe fat or actual oils) and something that adds the red color (as another poster mentioned it could be rust or something similar).

If you wanna be really sci-fi you could also make it include some nanobots that emulate the functions of blood when it comes to clotting up and could also be used to repair the body.


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