Bioluminescent organisms produce their own light through chemical reactions involving unstable, energetic molecules, while biofluorescent organisms re-emit light shone on them at a different wavelength.

Bioluminescence provides organisms with a method of hunting, defense, or mating

Biofluorescent animals—those that absorb light, such as ultraviolet rays, and re-emit other types of light, such as neon green—include some flying squirrels, scorpions, sea turtles, and platypuses.

View examples of luciferin, the light-emitting molecule behind bioluminescence

View illustrations of bioluminescent functions in marine organisms

View a gallery of bioluminescent organisms, including snails, worms, fungi, jellyfish, and mushrooms.

Because it is observed in organisms that are not closely related, biofluorescence is thought to have emerged independently many times in nature—over 100 in fish alone.

Bioluminescent reaction enzymes are often used in biomedical research

Bioluminescence became common in the ocean to support survival in dark environments

View a gallery of biofluorescent animals, which contain cells that emit various colors when exposed to ultraviolet light.

Massive blooms of microscopic algae called dinoflagellates produce the neon blue light seen in glowing tides.

Humans have used bioluminescence as a means of military advantage

Blacklights can illuminate certain biological materials, including blood, teeth, and fingernails, because they contain fluorophores—molecules that visibly glow immediately after exposure to higher-energy light.

Why 75% of ocean animals glow

View a sample of the bioluminescent tree of life

Bioluminescence may provide a sustainable alternative to electric lighting

Watch David Attenborough's documentary on bioluminescent creatures, which have been observed using light for hunting, mating, communication, and self-defense, and number in the thousands of species.

Solutions of bioluminescent bacteria can create FOMO-inducing living art

The first appearance of bioluminescence was at least 540 million years ago

Virtually all plants are biofluorescent because their photosynthesis is powered by chlorophyll, a pigment that glows red as a way to get rid of excess energy when exposed to ultraviolet light.

Fireflies light up to provide mating signals and warnings to predators

View a gallery of plants made to shine using ultraviolet-induced visible fluorescence photography, in which organisms re-emit the ultraviolet light they are exposed to in vibrant, glowing colors.

The 2008 Nobel Prize in chemistry was awarded for discovering and developing uses for green fluorescent protein—a biomolecule found in some Pacific Northwest jellyfish.

Bacteria have been genetically engineered to bioluminesce when wine has spoiled

Scientists can tag distinct proteins with fluorescent probes that emit different colors, allowing them to visualize multiple biochemical processes simultaneously.

View an animation of how certain chemicals fluoresce—that is, emit visible light after having absorbed higher-energy light, such as ultraviolet radiation.

Some organisms can change color by quickly revealing or hiding various pigments, as seen in octopuses, squids, and other cephalopods.

By converting ultraviolet light into visible light and reflecting specific visible colors, fluorescent pigments can often provide much brighter, neon-like color than traditional pigments.

Glow sticks shine brighter and burn out faster at warmer temperatures because the additional thermal energy increases the rate of the underlying chemical reaction.

Through sonoluminescence, concentrated sound waves can produce short, high-intensity flashes of light by rapidly collapsing microscopic bubbles to temperatures up to twice that of the sun's surface.

Blood can be blue, green, magenta, or transparent due to differences in the oxygen-carrying respiratory pigments they contain.

Some female fireflies mimic the signals of other species to lure in and eat them

When caught in the mouths of cardinal fish, seed shrimp release glowing, bioluminescent chemicals, which alert predators of the cardinal fish, prompting the shrimp's ejection.

Electrogenic animals generate their own electricity by changing the pattern of electrical charges in disc-shaped cells called electrocytes.

Single-cell organisms have circadian clocks that direct daily biochemical routines

Some corals absorb harmful ultraviolet radiation and re-emit it as visible light, thereby protecting symbiotic algae within their tissues and providing them with energy for photosynthesis.

Some North American bats can glow in the dark

Starting with red, colorful objects will appear to lose their colors the deeper they are submerged because water scatters light, reducing the amount available to reflect off objects and be observed.

Some organisms' colors come from structural color—tiny structures that distinctly scatter different colors of light, eliminating some while reinforcing others that become visible.

The term 'symbiosis' was coined during the study of lichens—composite organisms in which algae or cyanobacteria partner with a fungus, alongside bacteria.

Instead of consuming water and carbon dioxide to produce oxygen and sugar, anoxygenic photosynthesis involves alternative reactants and products.

Coral reefs get their colors from zooxanthellae—photosynthetic algae that line corals' digestive tracts and provide them with sugars in exchange for a home.

Scientists create movies of subatomic phenomena using X-ray free-electron lasers, in which images are produced by striking matter with high-intensity light created by accelerating electrons.

Learn how your body is, scientifically, like a firework with its own slow, controlled burn.

View the fluorescently stained internal structures of a tardigrade

Scientific applications of bubbles include logic gates, laser production, and medical imaging

Blood color differs across the animal kingdom, with some animals producing blood that appears green (a group of lizards in New Guinea) or blue (horseshoe crabs).

By separating light with tools such as prisms, scientists can reveal the presence and composition of celestial matter by identifying color fingerprints unique to specific elements and molecules.

Photoautotrophs, which include plants, algae, bacteria, and Euglena, are organisms at the base of the food web that convert light energy from the sun into chemical energy stored in sugars.

Harmful algal blooms can occur in warm, nutrient-rich, stagnant waters and are often associated with the rapid reproduction of blue-green algae—a misnomer for cyanobacteria, not algae.

Bacteria use chemical signals to communicate and coordinate with one another