How do animals glow?

Some living things can light up dark places without the help from the sun. While fireflies are the best known bioluminescent creatures, other species of insects, fungi bacteria, jellyfish and bony fish can also glow (1). 

There are two main ways that animals glow: 

1:Fluorescence  the process by which light of one wavelength (color) is absorbed and the light of same wavelength (color) is emitted later(2). To fluoresce, the frog or any other fluorescing creature, just needs two things. A molecule with excitable electrons and the right wavelength of incoming light. For excitable molecules, the frogs rely on a chemical called halogens which are found in the animal skin and glands. Incoming light excites the electrons and when those electrons settle back down, the molecules release light of their own. Fluorescence is rare in land animals; it is mostly found in sea creatures like the fish and turtles. (3)

    2:Bioluminescence requires oxygen and some fancy chemical equipment. The best thing is that this chemical equipment is similar in most organisms that Bioluminescence like the fireflies, jelly fish and bacteria. To emit light through bioluminescence you need a molecule called luciferin and an enzyme called luciferase. The luciferase takes oxygen puts it onto the luciferin. The end product is a molecule called oxyluciferin whose electrons are in an excited state. When the electrons come down to the ground state they release light, which makes the organisms glow.(3)



Before I did this study, I used to see fireflies and have no idea how it was possible that they could glow.  I found it really interesting to learn how the electrons get excited and then when they fall back down, they give off light.  

In my next round of research I am going to look into how the ability to glow helps animals reproduce

Examples of organisms that glow




2 Dragon fish




3 fireflies




4 Fungi



5 Anglerfish








2 Replies to “How do animals glow?”

  1. Hi Joseph,
    I really like your topic! When I was younger, I would always watch shows about glowing fish and wonder how it worked. I found it interesting that their light system is exactly the same as regular sun light. Honestly, I thought it would be different! Good luck on your next round of research

  2. Hi Joseph!

    I’ve always wondered this myself, so I’m happy to have the answer! I like how you explained things, it made it very easy to follow and understand.

    There’s still something I wonder about these glowing animals though. Animals don’t usually develop unique and strange features like fluorescence and bioluminescence unless it helps them somehow, right? So how does glowing benefit animals?

    I look forward to reading your future posts,
    -Jasmine 🙂

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