Synchronous Fireflies: Great Smoky Mountains National Park

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What are Syncrhonous Fireflies?

Synchronous fireflies are a species of lightning bugs that blink synchronously during their mating ritual.  There are only a few places in the world to see synchronous fireflies, and one such place are the Jake’s Creek and Little River Trailheads near Elkmont Campground in Great Smoky Mountains National Park.

Every year around the third week of May to the third week of June, depending on the temperature and soil moisture, the synchronous fireflies mate for 2-3 weeks. During this period, the males fly around flashing in unison while trying to attract females that remain stationary on the ground.  The females return their signal, and the males fly down to mate, sometimes fighting with others.

The males utilize their specific flash pattern to distinguish their species (Photinus carolinus) from the other 19 firefly species in the park, some of which are predatory.  This way, the female identifies its species to safely mate.

The Photinus carolinus firefly blinks 5-8 times, stops for 8 seconds, and repeats itself while other species blink once or twice or have a flash that appears blue.

The result of all this flashing is a spectacular light show that lasts for approximately two hours each night (9:30-11:30).  The display is simply mesmerizing and remarkable.  Really any video and photo you see on this post or others do not do this rare phenomenon justice. 

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What Do the Synhronous Fireflies Look Like?

I polled my friends who came with me, and they say it topped to the 2024 total eclipse!  A few ways to describe the light show is as follows:

1. A white LED Christmas light display that blinks in a pattern to music, stops, and starts over again every 15 seconds or so
2. A flashing constellation in the forest
3. A digital light art show

Everything You Need to Know About Viewing Synchronous Fireflies in the Smokies

If any of the above descriptions pique your interest, then go see the synchronous fireflies in Smoky Mountains National Park! Below is everything you need to know:

Great Smoky Mountains National Park Synchronous Firefly Lottery and Viewing Dates

To protect the fireflies and their environment since they spend most of their life (1-2 years) on the ground in a larval state while feeding on snails and worms below the leaf litter, the Great Smoky Mountains National Park has devised a lottery system.

The lottery typically opens on a Friday at 10 am in late April and closes at 11:59 pm on the following Monday.   Applicants apply for a vehicle parking reservation with Recreation.gov.  1,120 permits (140 vehicles per night) are awarded out of 20,000 applicants.  If it seems like a long shot to you, don’t worry there are a few ways to view the synchronous fireflies without winning the lottery (more later).

Lottery applicants find out if they have been selected in mid-May. And the viewing opportunity takes place sometime during the third week of May to the third week of June. 

The 2024 synchronous firefly viewing dates were from June 3-10.  We went on the 4^th and were treated to a pulsating light show!  One of the many rangers who work the event said, it was the best she had seen in five years, and that we hit the peak night.

We felt so fortunate because it was a very wet year, and the forecast called for storms.  Luckily, they held off as the lightening bugs don’t flash in heavy rain or in temperatures below 50 degrees F.  If it is just misting, they will likely still display. 

Other Fun Facts About Fireflies

1. Fireflies are beetles
2. Upon reaching their adult form (flying stage), they live only 3-4 weeks, and many do not feed.
3. Their biolumenscence is considered a cold light as the combined chemicals in their abdomens that make the light does not give off heat.  Nearly 100% of the energy created is light, contrary to an incandescent lightbulb which produces 10% light and 90% heat.
4. Each species flashes a different amount.  There were six species of fireflies during the firefly event at Smoky Mountain National Park

Ways to See the Synchronous Fireflies in Great Smoky Mountains National Park Without a Permit

As mentioned above, if you didn’t make the cut in the lottery or are learning about this phenomenon after the application deadline, below are a few more ways to see the synchronous fireflies.

1.  Visit the Great Smoky Mountains National Park the week before or the week after the firefly event.  They mate for three weeks, so there is a good chance you will see them and there are no parking restrictions at this time.  Additionally, while entomologists study the conditions and make their best guess as to the peak mating week, it is nature, and you could get lucky and catch the peak before or after the event.
2. Reserve a camp spot in Elkmont Campground.  Elkmont Campground is next to the firefly viewing area which includes Little River Trail and Jake’s Creek Trail.  You may reserve a spot six months in advance.  Of course, to ensure you are there during the Synchronous Firefly Event, you will need to wait until the viewing dates are announced.  If the campground is full, check back because people may cancel.
3. Reserve a backcountry campsite.  Buying a backcountry permit for a campsite related to Little River Trail and Jake’s Creek Trail allows backcountry campers to park at the trailheads.  Backcountry permits may be obtained 30 days in advance on Recreation.gov or in person.  In addition to the permit ($8), you will need to buy a parking pass ($5) which may also be purchased online or at the Sugarlands Visitor Center.
4. If all else fails, you may try volunteering, or visit other places in the USA with synchronous fireflies (more later).

Tips for Viewing the Synchronous Fireflies in the Smokies

During our visit to see the synchronous fireflies in Great Smoky Mountains National Park, we reserved a backcountry campsite, but did not camp.  Here are a few tips we learned in the process.

1.  Both the backcountry permit and parking pass require knowing your license plate number.  This makes it hard to do for out-of-towners who want to fly and rent a car.  I ended up making the long drive as I made reservations in advance because I was unsure if the backcountry sites sell out.  That said, the rangers never asked to see the permit or parking pass while we were there.
2. The permit instructions suggested we get to the trailhead early to get a parking space as they sell more parking passes than there are spaces available.  We arrived around 7 am and only a few spots were taken.  We made the most of our early arrival and took a 10 mile out-and-back hike up Little River Trail.  Upon our return, the lot was full, but it emptied out in the afternoon as no one is allowed to come and go between 4 pm and 11 pm except Firefly Event Pass Holders.  As a result, we could have arrived around 3:30 pm on a weekday, set our chairs out for the viewing, gone on a hike, and come back in time to see the fireflies.   But we didn’t know what to expect.  Instead, we hung out in the parking lot for hours playing cards, eating snacks, and even taking a nap!
3. Select the location where you want to watch the fireflies around 7 pm at the latest.  The best places for viewing are beneath a canopy of trees with little ground cover below.  There is an excellent spot about 100 yards up Jake’s Creek Trail on the left.  Unfortunately, we didn’t know to do this, so by the time we wandered in after sitting there all day, we had to find another area.  That said, we found a great location with the help of a ranger.
4. Don’t get discouraged.  At first you will only see a few fireflies flash and you think you might not be in the right place.  Just wait until 9:30 when it gets very dark.  You won’t be disappointed. Especially when you are blessed to see a bear stroll through the woods like we did!
5. If for some reason you don’t like your spot, you can move.  In fact, we left a little early so we could walk down the trail through the flashing fireflies.  Incredible!
6. Take some of the red cellophane the rangers offer you at the entrance to cover your flashlight, phone screen, and camera lights.  The bright light disturbs the fireflies and interferes with your night vision.

As newbies, we arrived in Gatlinburg after midnight the night before, left the hotel at 6:30 am the next morning, and hung out in the Elkmont area ALL day and night, only to return to the hotel around 11:30 pm after viewing the synchronous fireflies.  Without all the above tips, we made it difficult on ourselves, and seeing the lightning bugs pulsing display was still totally worth it!

Tips for Photographing Synchronous Fireflies

Providing tips for photographing synchonous fireflies is an exercise in futility as the photos just can’t do the mating ritual justice. That said, here a few helpful hints:

1. Use a tripod and a remote. A remote will reduce the camera shake. If you don’t have a remote, you can try a shooting on a 10 second timer, but you will have to time it with their blinking and the 8 seconds when it goes dark.
2. Get there before dark to autofocus on distant trees. Then switch to manual focus and keep the camera in one place.
3. Cover your bright lights
4. Use camera settings for shooting stars. Start around an Aperture to f/3.5, Shutter speed 30″, and auto ISO. Adjust from there.
5. Those who want to post edit and stack photos, can do so.

Other Places to See Synchronous Fireflies in the USA

If you can’t make it to Great Smoky Mountains National Park, there are a few other places to see synchronous fireflies in the USA.  They include Allegheny National Forest, Rocky Fork State Park, Oak Ridge Wildlife Management Area, and Congaree National Park.

Allegheny National Forest is Pennsylvania’s only national forest.  The Photinus carolinus species of firefly is one of fifteen found in the area. The best viewing dates are between June 10-22 with the peak time being 10 pm. Contact Allegheny National Forest for more information.

Rocky Fork State Park is located in northeast Tennessee in the Southern Appalachian Mountains.  It offers guided viewings which are limited to a lottery. Find out more at the park’s website.

Oak Ridge Wildlife Management Area features 32,000 acres of controlled access near Knoxville, Tennessee.  It is home to the only other species of synchronous fireflies, the Photuris frontalis, also known as the Snappy Syncs.  These fireflies are found in old growth forests near a water source.  Though controlled, there are a few access points and greenways open for hiking in the day.

Congaree National Park is located in South Carolina.  The Photinus carolinus fireflies put on a blinking display in late May and mid-June between 8 and 10 pm.  The habitat which is more swampy and known as an “old growth floodplain forest” is different from aforementioned areas.

Synchronous Fireflies in Southeast Asia

Finally, synchronous fireflies may also be seen in Southeast Asia.  In fact, they are not as rare as the synchronous fireflies found in the United States.  These fireflies from the genus Pteroptyx of which there are several species light up all at once, like flicking on a light switch.

They may be viewed all year long lighting up trees in mangrove forests and areas along riverbanks as well as nipa palms.  Peak times range from 7:15 pm to 11pm. It is even possible to see them on a kayak tour.

If seeing thousands of synchronous fireflies flashing in the forest floats your boat, you may also like seeing the Monarch Butterfly Migration to Mexico, another stunning phenomenon.  Don’t wait to visit Smoky Mountains National Park and find many things to do in Gatlinburg. ETB

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