Elkmont, also on the Tennessee side of the National Park, is one of the few places on the planet where you can view synchronized fireflies:
...these are no ordinary fireflies. The little creatures are simultaneously flashing in perfect unison over and over again.
According to Jonathan Copeland, a biology professor at Georgia Southern University and one of the world's foremost authorities on fireflies, about ten to 20 Photinus carolinus in a given area at Great Smoky Mountains flash in sync from about 9 to 11 p.m., from June 1 to around June 21. They flash about five times, pause for about ten seconds, and repeat the cycle.
Synchronous flashing is a modern-day phenomenon. Scientists once believed that the phenomena did not occur outside of Southeast Asia. But in the early 1990s, an amateur naturalist named Lynn Faust saw what she thought were synchronized fireflies while at Elkmont in Great Smoky Mountains. After reading a newspaper article about synchrony, Faust wrote to a scientific mathematician who suggested she contact Copeland about her finding. In 1995, Copeland and fellow scientist Andy Moiseff confirmed that Faust had in fact spotted synchronizers at the park.
Scientists believe that the synchronous flashing is linked to mating, but little, if any, conclusive evidence has been made available. Copeland is able, however, to reveal a little more on the hows of synchrony: "The firefly has a pacemaker in his brain [telling it to] flash, and this can be accelerated or retarded…. The firefly sees a flash and, say, speeds up; the other firefly sees a flash and, say, slows down. They speed up and slow down each other, and in doing so become synchronized."
In other words, the stimulus from the preceding cycle determines the behavior of the subsequent cycle. In this way, fireflies differ from, say, a school of fish or a flock of birds. "[Fireflies'] signals get added together and some sort of decision is made. Birds and fish are driven by reflexes, whereas fireflies' flash is driven by a preceding set of signals that get interpreted in their brains," Copeland says. Elkmont's species has attracted considerable attention over the past few years from both scientists and the public. Many visitors to Great Smoky Mountains National Park like to watch the synchronizers light up, and scientists, now more than ever, are convinced that further study of the insects will benefit the human population.
Copeland agrees. "You might gain insight that might be useful to humans, like heartbeat, control of menstruation, [and] release of insulin from the pancreas," he says. "Synchrony is a very unique type of biological timing, and fireflies do it better than any animals. The human body is full of biological rhythms that affect our health. The more we know about biological systems, the more we can gauge."
While on the subject of phenology in the Smokies, I've heard that during a certain time of the year, rattlesnakes migrate through one part of the park, such that for a space of several hundred feet, you would not be able to step on the ground without stepping on a snake. Exactly when and where that exciting event occurs, I'm not sure.
Given a choice between the two, I'd prefer to go observe the synchronous fireflies.