Animals that Glow in the Dark


Did you know that there are animals that can light up like a light? In this article we highlight (ha!) 5 animals that glow in the dark and explain how and why they do it. Check it out!

Firefly squid

Photo credit: Chiswick Chap

Measuring only about 3 inches long, firefly squids are found in the waters surrounding Japan, and they use their glowing ability in a surprising way: to hide. When they lie horizontally and light up the underside of their body, they camouflage with the lights shining down from the surface. You can see the difference it makes in the picture on the right. This allows them to hide from predators swimming below them.

These squids also use their lights to attract mates and to communicate with each other.


The female anglerfish certainly isn’t what we’d call cute, but she’s definitely pretty cool. She has a light that hangs from the top of her head that she uses to attract prey. In the dark waters, a bright light like that can bring in all sorts of curious creatures, big and small. But she’s ready for anything that crosses her path, as she is able to swallow prey 2 times her size!

Railroad worm

Photo Credit: Aaron Pomerantz

This railroad worm isn’t actually a worm – nor is it a railroad – but actually a type of beetle. While the males look more like you would expect a beetle to look, the females will always look like a larva, but they have something that makes them extra special: they glow in the dark! Their bright lights act as a warning to predators that they are toxic and to stay away. Only the females and juveniles can glow and when they do, they look like a passenger train at night, which is where their name comes from. Choo! Choo!

Lantern shark

Photo Credit: Chris Bird

That’s right; there are glow-in-the-dark sharks! The lanternshark is another deep sea creature that glows. These sharks only grow to 50 cm long, and they have light-emitting cells that line their belly and underside of their fins. Scientists aren’t 100% sure what the sharks use the lights for but they think it is probably a form of camouflage, just like the firefly squid.


Photo Credit: Emmanuelm

Of course, this list wouldn’t be complete without fireflies!  These insects are perhaps the most famous light-up animals. It’s not unusual to see these insects flash their lights in the summer but why do they do it? They put on a whole light show just to attract a mate!

So what makes them glow?

All of the animals on this list are bioluminescent! This is what it’s called when a light is produced by a chemical reaction in a living organism. The chemicals, stored in the animal’s body, are mixed together and create a bright and colourful reaction that the animal can use to do things like attract a mate, lure prey or escape from a predator.

Wouldn’t it be cool if we could glow in the dark? Think of all the energy we’d save by not using lights! Unfortunately, it doesn’t look like we’re going to be saying goodbye to lights any time soon but we can still save energy by being smart about how we use them.

Accept the Flip the Switch Mission to learn how you can save energy and help save the planet.


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