Synchronized Smokey Mountain Fireflies

Dylan Thuras is a guest blogger on Boing Boing. Dylan is a travel blogger and the co-founder of the Atlas Obscura: A Compendium of the World's Wonders, Curiosities, and Esoterica, with Joshua Foer.

So to contrast with the giant industrial holes and moon poop Josh and I have been posting about, I am going to highlight one of my favorite bioluminescent wonders in the world.

Happening right now, and for the next few days the Great Smoky Mountains of Tennessee will light up as P. Carolinus fireflies begin to blink in beautiful, astonishing unison. The fireflies, who can sense when their neighbor fireflies are flashing and attempt to flash before them, send waves of light to cascading down the Tennessee hillsides. One of the best spots to see them is in one small area, near the Little River Trailhead in Elkmont, TN.

Long thought to be an exclusively Southeast Asian phenomenon, the dazzling behavior was only discovered in an American firefly species (P. Carolinus) in 1992. The American fireflies were first brought to the attention of scientists by a reader of Science News, who thought it odd that an article on Asian firefly synchronicity mentioned nothing about the bugs near her own home. She wrote a letter to a Steven Strogratz, a Cornell mathematician who studies synchronization:

"I am sure you are aware of this, but just in case, there is a type of group synchrony lightning bug inside the Great Smoky Mountain National Park near Elkmont, Tennessee. These bugs "start up" in mid June at 10 pm nightly. They exhibit 6 seconds of total darkness; then in perfect synchrony, thousands light up 6 rapid times in a 3 second period before all going dark for 6 more seconds.

"We have a cabin in Elkmont... and as far as we know, it is only in this small area that this particular type of group synchronized lightning bug exists. It is beautiful."

In 1995, scientists confirmed the existence of the Great Smoky Mountain synchronized fireflies, and have subsequently discovered other populations in the Congaree Swamp in South Carolina and other high altitude locations in the Appalachian mountains. As this curious phenomenon remained undiscovered for years, it is quite possible that there are other varieties of fireflies blinking in unison throughout the United States, perhaps even in your own backyard.

More info on the Smokey Mountain fireflies here and here more info on bioluminescent spots around the world on the Atlas bioluminescent spots page.


  1. Near my sister in laws family farm in Blairsville, GA I noticed a group of thousands of fireflies on one tree near their property on a late night star gazing hike. I’m due to go back up there soon and will hit the spot with my GPS. I’ll be sure to put it up on the atlas…

  2. That was the most awesome video of black and near-black compression artefacts.

    Did I miss anything?

  3. Even in the Atlanta suburb in which I live, there are similar effects. If you go out on a nice, warm night like tonight and quietly watch among the pines, you’ll see the fireflies doing this. If it’s a really good night, you might even be able to watch the flash shoot across the woods like a high-speed lightning-bug version of “the wave.” Beautiful little bugs. I always thought people who kill lightning bugs are sick and useless things.

  4. (Warning: gratuitous self-pimpage)

    I actually tried modelling firefly synchronisation (with only moderate success) using Processing a while ago. Some videos are here:



  5. This video clip is just begging for someone to turn it into one of those flash-the-scary-face-and-add-a-scream-clip videos. You’d totally sucker loads of people into watching it.

  6. My girlfriend saw this in southern Illinois some years ago. She was pretty excited to find that it happens elsewhere.

  7. Sources say that it’s pretty amazing to unexpectedly come across this on a hike while high as a kite.

  8. – …. . / …. ..- — .- -. … / … ..- … .–. . -.-. – / -. — – …. .. -. –. .-.-.- / -.-. — — — . -. -.-. . / … .. –. -. .- .-.. .. -. –. / – …. . / — — – …. . .-. / … …. .. .–. .-.-.-

  9. After watching the video I can confirm that I have seen this in my own backyard, just not as many fireflies. I was hoping for something a little more dramatic.

    Please bring back the Athanasius Kircher Society, if everybody knows about these out of the way things they are not very obscure, are they? Perhaps Atlas Obscura means they made it hard to see the fireflies in this video.

  10. I saw synchronization while a student at George Peabody College (now part of Vanderbilt) in Nashville, summer of 1975. The major buildings there are arranged on either side of a long rectangle. A flash would start on one end and work its way down to the other, a moving line of light.

  11. Synchronized? How are these synchronized?

    They aren’t.
    They don’t.

    Even those blinking highway barriers seem synchronized every once a while. But they ain’t.

  12. Elkmont is about 45 minutes away from my house. I’ve watched this every year for the last 5 years. Stunning to see in person.

  13. synâ‹…chroâ‹…nize
      /ˈsɪŋkrəˌnaɪz/ Show Spelled Pronunciation [sing-kruh-nahyz] Show IPA verb, -nized, -niz⋅ing.
    –verb (used with object)
    1. to cause to indicate the same time, as one timepiece with another: Synchronize your watches.
    2. to cause to go on, move, operate, work, etc., at the same rate and exactly together: They synchronized their steps and walked on together.
    3. Movies, Television.
    a. to cause (sound and action) to match precisely: to synchronize the sound of footsteps with the actor’s movements.
    b. to match the sound and action in (a scene).
    4. to cause to agree in time of occurrence; assign to the same time or period, as in a history.
    5. to adjust the periodicities of (two or more electrical or mechanical devices) so that the periods are equal or integral multiples or fractions of each other.
    –verb (used without object)
    6. to occur at the same time or coincide or agree in time.
    7. to go on, move, operate, work, etc., at the same rate and exactly together; recur together.
    Also, especially British, synâ‹…chroâ‹…nise.

    1615–25; < Gk synchronízein to be contemporary with, equiv. to sýnchron(os) synchronous + -izein -ize Related forms: syn⋅chro⋅ni⋅za⋅tion, noun syn⋅chro⋅niz⋅er, noun Unabridged Based on the Random House Dictionary, © Random House, Inc. 2009. Cite This Source | Link To synchronize

  14. If I were a firefly I’d probably be one of those poor outliers trying helplessly to keep the beat with everybody else.

  15. I’ve been 5 years in a row to Elkmont and the show is stunning. The bugs are much brighter and larger than in other places. You may have thought you’ve seen synchronization elsewhere but once you see the real thing here, you know it’s totally amazing.

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