For a short time each spring, natural fireworks spark the forest darkness in Great Smoky Mountains National Park. These mysteriously synchronized lights—flashing together as one, from just above ground level, up into the trees—mark the dances of thousands of rare fireflies. This is a sight worth visiting Tennessee to watch.
These synchronous fireflies aren’t your familiar backyard blinkers. Imagine deep darkness, suddenly illuminated by countless tiny, greenish lights all firing at once. That’s how the unusual “synchronous firefly” species meet mates and dazzles human visitors.
The synchronous firefly exists in a few locations. One is the Smoky Mountains. While 19 species of firefly live in these mountains, only one species puts on this famous light show. Fireflies take a year or more to mature into adults, but once they do, they live only 21 days. That’s their brief window for mating, and your opportunity to marvel at their coordination.
Scientists don’t know why these fireflies, unlike their more common kin, can synchronize group flashes. It’s possible that every male is eager to be the first to fire up, and they compete, blinking almost together, as they try to impress the females waiting on the ground below. The males fly and flash for about seven seconds, stop suddenly, then the females respond with their own synchronized blink.
The light display goes into the night. You won’t know how their dates turned out, but you can enjoy the sparkling way they court each other.
If you’re lucky to be here at just the right moment, you might glimpse synchronous fireflies on your own. But the best plan for catching this magical display requires help from the National Park Service.
There’s one peak viewing week each year, usually sometime between mid-May and mid-June. In April, the Park Service opens an online lottery for tickets to see the fireflies during the very limited peak. Your paid ticket gets you a parking space at Sugarlands Visitor Center and a shuttle ride to Elkmont, a prime viewing spot. There, rangers guide you to wooded paths where you wait for the lights to commence.