Is it possible for a bioluminescent organism to be so pervasive in an environment, that creatures who eat it (because it's in plants for example) also start to glow? It doesn't have to be a bright glow. I'm not thinking like Avatar, more like the sand that glows when you move it.

Or is there another way besides eating that this organism could get into everything? (This may have to be a separate question)


To answer someone's question: this is a world where all mass/form occurs only where light touches it. If something falls into complete darkness, it dissolves into formless, non-being. So the purpose of the bioluminescent organism is for those spaces that are in caves, in buildings, under trees, or even in deep waters. If they have something that emits light, then they would retain their form. If it's something internal, it means your internal organs would also retain their form even though they are not exposed to light either.

  • 1
    $\begingroup$ "Is that a light bulb in your pocket, or are you just happy to see me?" $\endgroup$
    – user535733
    Sep 6, 2019 at 11:48
  • 3
    $\begingroup$ From an evolutive point of view, you do need a good excuse to make everything glow, in special predators. They do live in permanent darkness? $\endgroup$
    – jean
    Sep 6, 2019 at 13:40
  • $\begingroup$ Greg Egan's excellent Orthogonal universe has an excellent suite of physics in which every chemical reaction produces light - a quick primer can be found here $\endgroup$
    – Dubukay
    Sep 6, 2019 at 17:55

3 Answers 3


Several similar effects can already happen in our world.

Carotenemia is a condition cause by excessive consumption of carrots. Several chemicals that give carrots it's orange colour are absorbed by our bodies and because they are fat-soluble they get stored in fatty tissues including outer layer of skin.

It does not exactly give us bioluminescence but it's possible we discover a chemical with similar physical properties that is also Fluorescent or Phosphorescent.

Fluorescence means absorbing high frequency (short wavelength) light and reemiting lower frequency (higher wavelength). The most popular examples are combination of "black light" that is near-UV light source with a material that absorbs it and reemits visible light with disco-violet hue.

This doesn't address your scenario of living organisms in deep caves. But it may seem like it produces light out of nothing on the night side of the planet if you have some source of UV, for example a black hole couple of light years away. In real world such a black hole would also be visible in the regular spectrum so it depends how realistic your universe is.

Phosphorescence is slightly more complicated mechanism of delayed reemision. It could allow your organisms to absorb energy during daylight and slowly emit weak light throughout the night.

For Bioluminescence you need the organism to actually perform the chemical reaction. Microorganisms consumed by the animals are dissolved in the stomach and all their reactions stop. What's probably more realistic is skin infection by bioluminescent fungi.

Fungi are known to infect higher organisms and leech of their matter and energy. They could use some of it to produce light. The problem is that they don't really have an evolutionary reason to do it. The point of bioluminescence for fungi them is to attract insects to consume them. If they are already feeding off your skin they will "want" to attract less attention, not more. Of course you can always ignore it and handwave some symbiotic relationship between the fungi and the animal.


Flamingoes get their pink color from the shrimps they eat.

Therefore it's perfectly plausible that the food influences the color of the eater.

Breathing would be less likely, since only gases cross the barrier with the blood stream.

Another trivial possibility is of course bathing, with the glowing organism sticking to the surface of the other creature.

  • $\begingroup$ However, gases aren't the only thing to cross the barrier with the blood stream. That's how some viruses and bacteria spread: through coughs and sneezes. But this does affirm the basic idea I'm toying with. $\endgroup$
    – DWShore
    Sep 9, 2019 at 14:03

Species mutualism is all over the place, but not as obvious as bioluminesence. Right now, most humans have some tiny demodex mites sitting around their eyelashes, quietly eating discarded skin and hair. All live humans have several pounds of micro-organisms, mostly varieties of escherichia coli, in their intestines, helping digest food. There are many kinds of mutualism, most of them subtle.

One potential explanation for a mammal-friendly mutualism : A common bacterium sits on hair follicles and eats extra oil, glowing if the host is healthy. There could be multiple indicators of health, but simply having enough energy and resources to spare to put out sebum and similar oils, means that the host is a good healthy mate. Cue up to increased social status. A culture which figured out clothes, but figured out they need to oil the clothes to maintain status.

  • $\begingroup$ Deliberately making clothing oily as a status symbol certainly opens other avenues of thought regarding politics both in and out of certain societal circles. One culture tries to remove their glow as much as possible and be "clean" while the other tries to glow as much as possible, making them literally... stinking rich. $\endgroup$
    – DWShore
    Sep 9, 2019 at 14:05

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