Student Article

Many creatures can glow in the dark using a special process called bioluminescence.

Glow in the dark? That’s a real thing!

Glow-worms and fireflies are some of the most well-known glowing animals, but there are also glowing jellyfish, squid, fish, millipedes, mushrooms, and even bacteria. One glowing earthworm found in Australia can grow up to 6 feet long!

The science behind the shine

The science behind the glow starts with a chemical called luciferin. When luciferin reacts with oxygen, it creates light instead of heat. Another substance called luciferase helps speed up the reaction and changes the color of the glow. For example, glow-worms glow green, while fireflies can glow yellow.

Why the ocean glows blue

Marine animals often glow blue thanks to a common compound called coelenterazine. Some squid and fish don’t make the glow themselves — they rely on glowing bacteria that live inside their bodies. These bacteria live in special light-making organs called photophores, which may include lenses and reflectors to help control the light.

Lights with a purpose

Glow-worms use their light to attract mates or scare off predators. Female glow-worms that can’t fly use their glow to signal flying males. Meanwhile, the glowing larvae warn enemies to stay away.

Bugs, mushrooms, and sneaky tricks

Some fireflies even use their glow to trick other fireflies. A female firefly may copy the light pattern of another species to lure in a male — then eat him! Glowing mushrooms might use their light to attract bugs that help spread their spores. Other fungi may glow simply as a result of waste chemicals in their bodies.

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