The world is a wonderful place, and nature’s magic is no more in evidence than when it comes to bioluminescent animals – animals that can actually glow in the dark!
What is a ‘bioluminescent animal’?
The term ‘bioluminescence’ refers to the production of light by living organisms which is emitted from their body. This light is created by the organism either through a series of chemical reactions (typically a substance called luciferin reacts with oxygen as a chemical reaction to release energy in the form of light), or by a form of glowing bacteria that the animal hosts. So bioluminescent creatures are simply animals that produce their own light.
Why do some animals glow?
Whilst glowing animals may seem other-worldly, there are a range of practical reasons animals have evolved this special power. Animals on this list and produce light and use bioluminescence to:
- Fend off predators
- Lure prey
- Camouflage themselves
- Attract mates
- Communicate with one another
In fact, making light has proven to be such a useful trait that it has evolved independently at least 40 times.
Bioluminescence is most common in the oceans – where in the deep it’s the only form of light – and according to Nature journal, an incredible 76% of ocean species are bioluminescent to some degree. A number of terrestrial creatures have also evolved to glow, but fish are the only bioluminescent vertebrates. Perhaps surprisingly, there are no known light-producing plants – only bioluminescent fungi.
The world is a wonderful place, and nature’s magic is no more in evidence than when it comes to bioluminescent animals – animals that can actually glow in the dark!
What is a ‘bioluminescent animal’?
The term ‘bioluminescence’ refers to the production of light by living organisms which is emitted from their body. This light is created by the organism either through a series of chemical reactions (typically a substance called luciferin reacts with oxygen as a chemical reaction to release energy in the form of light), or by a form of glowing bacteria that the animal hosts. So bioluminescent creatures are simply animals that produce their own light.
Why do some animals glow?
Whilst glowing animals may seem other-worldly, there are a range of practical reasons animals have evolved this special power. Animals on this list and produce light and use bioluminescence to:
- Fend off predators
- Lure prey
- Camouflage themselves
- Attract mates
- Communicate with one another
In fact, making light has proven to be such a useful trait that it has evolved independently at least 40 times.
Bioluminescence is most common in the oceans – where in the deep it’s the only form of light – and according to Nature journal, an incredible 76% of ocean species are bioluminescent to some degree. A number of terrestrial creatures have also evolved to glow, but fish are the only bioluminescent vertebrates. Perhaps surprisingly, there are no known light-producing plants – only bioluminescent fungi.
With all of this background and context in mind, below we feature some of the world’s craziest and coolest bioluminescent organisms, or you can skip to the bottom of the page for a complete list of light-emitting animals:
Firefly

Fireflies glowing at night with a green light
Fireflies are those species of the Lampyridae family that are able to fly, where the male and female are similar in appearance and emit light as short flashes to attract mates. The females of some firefly species actually mimic the light patterns of other firefly species, luring males to the ground where they kill and eat them… it’s a dangerous world!
Squid

A bioluminescent squid
Most species of squid produce bioluminescence, using it for a variety of purposes. Some deep sea squids excrete a glowing ink to confuse predators, the bobtail squid uses bioluminescence as a form of camouflage and the firefly squid uses thousands of tiny lights on its body to lure prey.
Jellyfish

A beautiful light producing jellyfish with red light and a blue green light
Over 50% of all jellyfish species produce light, predominantly as a defense against predators. Some jellyfish – such as comb jellies – produce bright flashes to startle would-be predators, whilst others such as siphonophores can release glowing particles to mimic small plankton and confuse predators.
Angler Fish

The angler fish uses its light organ to attract prey
The angler fish lives in the deep sea (the lightless bottom of the Atlantic and Arctic oceans), and has a huge head with crescent-shaped mouths complete with plenty of sharp, translucent teeth.
Their name comes from the fleshy piece of dorsal fin the projects over their mouth to attract prey. There are over 200 species of anglerfish, usually dark gray to dark brown in colour, and anywhere from 0.3 to 1 meter in length.
Lanternfish

The peculiarly lit lantern fish
Lantern fish are fairly small fish, ranging from just 2 to 30 centimeters in length. They are very common and numerous deep-sea fish, with over 200 species found in oceans worldwide.
Each species has its own unique lighting pattern that’s used in communicating and mating. Shallow-living species are bright bluey-green or silver, while deeper-living species are dark brown to black.
Click Beetle

The brightly bioluminescent click beetle emit light from spots on their back
The Pyrophorus is a type of click beetle found in the Americas, also known as fire beetles because of their bioluminescence. Their glow is similar to the firefly, though they do not flash, but rather maintain a constant glow from the two luminescent spots on their back. At night they use their light to attract other insect prey to eat. Their eggs and larvae are also luminous.
Motyxia Millipede

Grab your shades, the motyxia millipede is here!
One of the few known bioluminescent millipedes is the Motyxia. They’re found in forests and meadows in the southern mountain range of California, USA, reach 4 centimeters long, and produce cyanide.
In a study, their bright glow was found to strongly deterred nocturnal mammalian predators, and it’s thought the bioluminescence evolved as a warning signal to predators that their body contained cyanide.
Sea Snail

A stunning bioluminescent sea snail, glowing with both red light and blue light
One of the most electric-looking creatures on this list, the sea snail is one of the dozens of species that use bioluminescence. It’s thought that sea snails actually use their opaque shells to diffuse and spread bright bioluminescent light in all directions, seemingly enlarging themselves to predators. Another school of thought says that sea snails use their glow for communicating without needing to leave the safety of their shell. Whatever it is, it sure is beautiful!
Glow Worm

bioluminescent glow worm produces light in its abdomen
We need to be careful with glow worms as the word means different things in different continents. In Europe, glow-worms refer to the non-flying wingless species in the Lampyridae family, which emit a steady glow (unlike the short bursts of the fireflies). The Lampyridae family has over 2,000 species, with new species still being discovered.
In the Americas, glow worms refers to another luminescent beetle group (Phengodidae) and in Australia and New Zealand the name refers to the glowing larvae of fungus gnats, Arachnocampa.
Dinoflagellates

bioluminescent dinoflagellates lighting up the sea
It’s easy to see why dinoflagellates are more commonly known as fire algae. These single celled organisms are algae found in both marine and freshwater environments where they give the water a spectacular blue glow to ward off predators. The bioluminescent organisms are triggered by contact with other objects or organisms, by the movement of the surface of waves, or changes in temperature.
Fungus

bioluminescent fungi by day and night
OK, so fungi is not an animal, but we had to include them in this list as glowing fungus looks so cool!
There are over 70 species of fungus known to illuminate, and the brightest are found in tropical regions. Some fungus glows to deter predators, some to attract insects to help disperse their spores, and others as a byproduct of the wood they metabolize.
List of bioluminescent animals
Terrestrial animals
Arthropods
- Fireflies
- Click beetles
- Glow worms
- Railroad worms
- Some mycetophilid flies
- Some centipedes
- Some millipedes
Terrestrial mollusc
Quantula striata
Annelids
Marine animals
Fish
- Anglerfish
- Cookiecutter shark
- Catshark
- Gulper eel
- Lanternfish
- Marine hatchetfish
- Midshipman fish
- Pineconefish
- Viperfish
- Black dragonfish
Invertebrates
- Many cnidarians
- Sea pens
- Coral
- Some jellyfish
- Ostracods
- Copepods
- Krill
- Some molluscs
- Some clams, bivalves
- Some nudibranchs & sea slugs
- Some sea snails
- Some cephalopods
- Some octopuses
- Vampire squid
- Colossal Squid
- Mastigoteuthidae
- Firefly squid
Freshwater animals
- Latia
Other organisms
- Some fungi
- Some bioluminescent bacteria
- Protists
And that’s your lot for our round-up of bioluminescent animals. Have you had the opportunity to see any of these cool creatures lighting up the wild? Please share your experiences in the comments section below!
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