How could a creature make its feathers or hairs glow?

Question

The Context

In the world I am designing there are creatures known as a Dazzling Griffin. These griffins act in a similar manner to some birds of paradise when mating, putting on elaborate displays involving song, dance, and a glowing pattern across their feathers.

• Their glowing feathers have at least some capability of turning off and on.
• They can not fly instead relying on their climbing capabilities to traverse their jungle environment.
• The griffins' tails have glowing markings that resemble a Nitoclus, which is a poisonous constrictor snake that expels a glowing poison when threatened.
• The griffins are omnivorous.

The Question

How could a Dazzling Griffin cause its feathers to glow and have enough control of the glow to have it blink on and off?

Answer 1

Bioluminescent bacteria:

The Griffin's feathers, no longer needed for flight, are now harboring a symbiotic bioluminescent bacteria that grows in patterns on the feathers based on how the feathers grow (certain surfaces promote growth, others inhibit). Normally the feathers are kept fluffed and preened, keeping the bacteria alive but not active enough to glow.

But during mating season, the bacteria reach the peak of growth. They don't normally glow, but the griffin can trigger the glow by rubbing glandular oils full of hormones, moisture and nutrients on the patches. Like most animals, the patterns have evolved.

The bacteria glow brighter as they lose moisture. The spots begin to glow lightly, and by fanning and fluffing the feathers, the griffin controls the rate of drying. This allows flourishing displays of glowing feathers.

If the griffin needs to use the bacteria as a warning display to frighten off predators, they can preen the spots near the serpent pattern. It then appears to be a serpent spitting toxic poison.

Answer 2

It can use the same process used by fireflies, which can modulated the light they emit from their abdomen at will.

The glow will be caused by an optically active molecule, which will be excited as a consequence of a nervous stimulation: the same way you can blink your eyes at will, the creature will make its feathers glow.

Answer 3

Bio luminosity and refraction

Bio luminescence is active in many small creatures. Though it is important to note that their light is weak, so it is near exclusively shown at night.

There are microorganisms that sometimes reach the coast in great numbers. At night it is a spectacle. Triggered by excessive motion, like a wave or walking in the water, causes them to react with a glow.

But many bugs and larger sea life have it as well.

The Dazzling Griffin has either a symbiosis with bacteria that can do it, or made its own system. The luminosity is generally not active. In fact, it is only active in certain display scenarios. It is mostly vestigial, a mostly useless thing that remains because of sexual preferences. It will activate the luminosity at time to woo a partner, scare opponents, or show the well being of the creature (much like gazelles pronking).

Selective activation will help reduce the energy requirements. Lighting up in real sunlight requires a lot of lumen. Light still is much easier to produce than movement in energy terms, but a good shine is likely similar to a soft workout. If you do this in addition to normal movement it can be taxing.

Feathers refracting a lot of light can also assist, making the Dazzling Griffin choose the place to show its glory well. With the spectator between the creature and the sun, so the maximum amount of sunlight is reflected. If refraction is used, there should be a layer that stops the light as well. This can be put forward to stop glowing.

This can then result in the most logical creature. If the sun is up it'll refract light with its feathers, showing a glow thanks to refraction of available light. When it gets dark the energy requirements for bio luminescence drop, making for a realistic scenario for glowing displays with bio luminescence. This also doubles down on the magic of the creature. It glows in any amount of light, but it does glow very differently.

Answer 4

It rolls in glowing fungus.

https://en.wikipedia.org/wiki/List_of_bioluminescent_fungus_species#Species

There are apocryphal reports of glowing birds, especially owls. One theory is that the owls are contaminated with glowing wood fungus that is in their nest holes. Glowing fungus is not apocryphal and many species are described.

Your griffins know where to find these fungi. When it is mating time they rub the fungal bodies on their feathers, where they continue to glow for a time. This is "turning on" the glow and hopefully a prospective mate as well. The fungal pieces eventually die and are groomed away.

Very plausible but not a very sexy mechanism. Unless you are a griffin.

Answer 5

OLED+Bio-Electricity+Fiber-Optics
This critter has a metabolism that leaves him practically glowing in infrared. The reason? He's also a bio-electric generator driving a wrap-around OLED screen on his skin.

The hairs and feathers rooted in the skin are fibers with polished points and strategically placed partially reflective kinks that direct light to the appropriate points to make a controllable display. That display works much like the chromatophores in squid to produce dazzling displays.

The difference is that they work by emitted rather than reflected light. The light system has been driven by evolution to produce the absolute blackest blacks and brightest colors crossing the entire gamut of the griffin's eye range. Just playing a movie trailer would make them look damned sexy!

Instead, the next level is achieved by the griffin imagining (and displaying) exactly what his chosen mate would most want in a relationship. A caring and heroic spouse providing for their kids and family, guarding them from harm, etcetera, etcetera ...

This doesn't come without cost though. That display, when run flat out, requires tons of fuel. By the time mating season is over, all the guys are rail thin and constantly eating.

Answer 6

Phosphorescence

The Dazzling Griffin has feathers incorporating phosphors, which absorb light energy during the day. At night, it is time to for the Dazzling Griffin to demonstrate its display. If it spent more time among the upper branches to soak in the light, the display will be all the brighter and attractive when the sun goes down.

The Dazzling Griffin has iridescent feathers, much like birds-of-paradise or peacocks. However, a novel optical structure of Dazzling Griffin feathers exists to emit light in only one direction. Since the Dazzling Griffin has small muscles that can control the orientation of these feathers, it can turn its lights "on" and "off", or become a disco ball.

https://en.wikipedia.org/wiki/Phosphorescence

Answer 7

A mix of chemically-driven bioluminescence, and Cephalopod-like Chromatophors.

Chemical lights can get pretty bright. Not usually eye-hurtingly bright without a lot of added heat, but industrial-strength chemical glowsticks can be seen for miles.

Your jungle-griffin can have pockets of the same chemicals present under its skin to light up in funky patterns.

You know what also has pockets of colour under its skin?
Cephalopods like octopus and cuttlefish.

These critters have clusters of several primary colours and an arrangement of muscles around them which squeeze them. Kind of like a squeezy stress-toy. When the pocket is squeezed, the colour is pushed into a patch nearer the surface of the skin. When it relaxes, it elastically returns to rest.
In this way, an octopus can choose which colours are visible, and even do a mix of several colours at a time.

Your Jungle-Griffin could do the same thing, but with glowing colours. So they can produce different patterns, or opt to glow or not glow at will. In reality, the glowing chemicals are always active, but not always visible.

This doesn't work so well with feathers or hair. But as Jasen points out, you could conceivably achieve a biological Fibre-Optic hair/feather which is lit from the root via the same chromatophor/bioluminescence.

Answer 8

Pic 1: bioluminescent algae

Pic 2: algae living in the fur of a sloth

In short, the griffin cultivates bioluminescent algae in its feathers, and through some method of stimulating the algae can make it glow (it when its body puts off a certain pheromone or sweat or something).

Answer 9

Normal feathers have hollow shafts but solid structures in the vane. Your griffons have hollow channels along the outer surface of the barbs of their feathers that are coated internally with luciferin-producing cells and luciferase-producing nodes. When combined with oxygen in the atmosphere this produces light for a brief period until the reagents are exhausted.

In the rest state the majority of the tubes are filled with oxygen-depleted air. In order to activate the light emission a small amount of fresh air is pushed into the base of the feather by a modified arrector pili muscle. This provides fresh oxygen that then reacts to form a pulse of light. The griffon can control this to a certain degree, tensing areas of skin to raise and briefly illuminate the feathers for aggression or mating displays.

The same chemical process is used for more permanently illuminated areas such as the tail, only the oxygen supply mechanism differs. Rather than tightening the skin to produce light these areas are structured so that they can be opened to the air directly to produce low levels of light, or closed to conserve resources.

The downside of this adaptation is that the structure of the feathers is no longer able to encourage proper laminar airflow, vastly reducing their aerodynamic effectiveness. Over time this resulted in the griffons losing their flight ability, leading to a variety of evolutionary changes: redistribution of flight muscle mass, smaller wings that don't impede movement through trees and such, all of the long feathers have been replaced with short ones, wing structures are much too light to support much weight, etc.

Only healthy, well-fed griffons with good genetics are able to sustain the light production for more than a few seconds at a time. A more impressive and lengthy light show is a demonstration to potential mates that the griffon is in peak health and is a prime candidate for breeding. If there is competition in the area the males will fight not to drive the other away but to damage their feathers, reducing their ability to put on a good mating display.

As to diet, there's no reason why all griffons can't be omnivores just like some birds are. In fact some of the necessary nutrients to support their production of luciferin comes from certain types of plant. Access to these plants is a major resource requirement for your griffons to occupy an area. Without them the griffons can't make light for their mating dances, which will fairly quickly result in their population falling below sustainable levels.

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Of course your humans have no idea about all of this because, well, they're usually too busy trying to avoid the sharp bits. And it's a real shame because what the humans haven't quite figured out is that some of their staple crops are execellent sources of the required nutrients. That's why humans have so many problems with griffons terrorising their farming communities. If they'd just put in the research to figure it out instead of sending hordes of murder hobos in to kill everything, maybe they'd realise that if they'd just quit planting all that blue corn everywhere then maybe they'd save a few gold on hunters.

Maybe then we could get on with breeding domestic house-griffons that could replace felis catus as the pet of choice for keeping rats out of the kitchen.

Answer 10

hair and feathers are dead keratin, they have no connection to the normal energy source in the blood.

perhaps OLED feathers powered by and an electric eel physiology, I guess it's possible.

Or quantum dots, but that's more a day-glo effect than actual luminence.

Perhaps optic-fibre feathers lit from bioluminescence at the feather root.

Answer 11

Bioluminescence is an energy-devouring characteristic of a living thing, and it seems to have not to have evolved in large land animals. What good would bioluminescence do for such prey species as deer, rabbits, mice, or pigeons? Or their predators? Concealment is the essence of survival in the cat-and-mouse game. In the deep sea it has usefulness as a lure for mates or prey; short-lived insects can use it because their success comes from mating in a short time frame.

I apologize for destroying a literary device, but bioluminescence is too costly for large creatures to use for drawing attention to themselves.