Adventures, Travel

Glow Worm Poop Mystery – SOLVED!

glow worm
The cave is aglow with light-bummed maggots.

This is pretty funny … someone came to my blog today to find out whether glow worm poop glows. [Since I wrote this, few days have passed when a keyword search of “glow worm poop” hasn’t brought somewhere here. What a thing to be known for!]

The answer is no – that’s because the glow worm doesn’t poop. The glow that they make is their form of excretion. But rather than just launching solid or liquid waste, the glow worm converts the leftover matter into light that’s used to attract its prey. The glow worm dangles silky threads from their spots in their home caves. Insects see this and thinks they’re seeing stars, and fly toward the light. They get caught in the threads. Then the glow worm eats them, absorb the nutrients, turns the excess matter into light and begins the cycle again.

glow worm poop
The glow worm webs … revealed!

Really, that’s pretty fabulous. It takes stuff in, but leaves nothing but heat and light behind. That’s an incredible bit of evolution. And certainly, it has to be the envy of every mechanical engineer. That means no glow worm poop … at least not in the usual way we think of droppings.

If you’re interested in seeing glow worms, there are a number of places in the world to do so. Of course, I’m pretty partial to Waitomo, New Zealand. Here are a few related posts:

Rappelling into the Dark

7 Hotels in New Zealand

Rap, Raft & Rock

There’s not a lot else going on in Waitomo, but it is one of the more relaxing places I’ve ever been. Go there to get away from it all … and to enjoy some quality caving. If you look at the hotels story above, you’ll also find out about Woodlyn Park, where you can stay in everything from a converted cargo plan to a hand-built Hobbit Hole. So that’s another good reason to pick Waitomo as the place to find your glow worm adventure.


  1. Not sure how I ended up on your site, but glad I did.

    The glow Worm is a pretty cool and environmentally friendly creature. Kills insects, provides no environmental foot print, recycles, no emissions energy conversion…should be an emblem for some sort of green movement.

    Very cool.

  2. Ty

    There is a scene in the movie ‘Surf’s up’ where the penguins fall into a pool of glowing glow worm poop. That’s why I searched for it. Nice info!

  3. Jay

    I’m struggling with the simplistic and somewhat misleading nature of this post. For example excretion literally mean to poop. The bioluminescence isn’t a conversion of light either, rather a chemical reaction which helps burn off its waste (aka poop). Secondly bugs don’t see stars (esp ones that live in a cave), at best they are governed by moonlight but starlight is too far away. Another issue is that they don’t burn food off to create more light. It’s a chemical reaction that glow worms can control…ie they glow brighter when they’re hungry. Also not sure where you got the idea of them leaving nothing behind but light and heat…mucus tubes, snare, pupal cases are all left behind and bioluminescence is a cold light so no heat at all.

  4. Well, Jay, it sounds like you won’t invite me to write for your peer-reviewed etymology journal!

    Sorry to be the source of this existential struggle of yours … maybe you need to re-think whether you’re being a bit pedantic here. Just a thought. (For what it’s worth, the info from this post comes from the guides who lead people into the glowworm caverns. They’re probably not as expert as they could be, and likely presented the info in the simplest terms possible. The idea being to convey the basic concepts, not so much to be super-technical.)

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