Morse Code Humans invented a system called Morse code. It uses long and short flashes or taps to communicate information from far away without using sound. It's like the language the fireflies use. Hello - Morse Code
Flashy Fireflies

Twinkling fireflies signal summer evening to many people around the world. Have you ever wondered why and how fireflies flash?

Fireflies use a system of flashes to communicate. They use their light to say, "Here I am", to attract, and even to deceive!


How do they do that?

A firefly emits light from a tiny organ called a lantern. It's on the underside of its abdomen, where a biochemical reaction takes place. The reaction releases energy in the form of light.

What's the Pattern

Every species of flashing firefly has its own pattern. These unique patterns let males and females of the same species recognize one another in the dark.

Try It

Here are the flash patterns of two different species. Watch the firefly and click on the pattern that you believe it is flashing.

You got it!
Talk to Fireflies

Can you communicate with fireflies? Firefly scientists do! To study firefly behavior, scientists mimic female patterns with flashlights and watch the males react with their own flash patterns.

Try It

You can be a firefly scientist. Click on the flashlight in the lower right corner of the firefly field in sync with the female light pattern shown below.

Repeat a few times. If you flashed the pattern correctly, the male fireflies of the same species will flash back to you!

You got it!
Try Again.
Photinus consimilis
Fireflies Around the World
Click over the place markers on the map to learn more!

In some states in the southern U.S., tourists come to watch the spectacular display of flashing fireflies. The male fireflies flash to the same rhythm. This timing increases the visibility of the light, which may increase their chances of finding mates.


The larvae of Chinese fireflies live under water and eat snails.


Festivals that celebrate firefly season are common in the countryside around Tokyo. In Japanese poetry, fireflies symbolize silent yet romantic love.


In ancient Mayan civilization, the firefly is one of the most common insects shown in art, especially in ceramics.


In much of Europe, female fireflies don't fly. As adults, they look more like worms. They also glow steadily instead of flash.

Imaginary Line

In North America, there are no blinking fireflies west of this imaginary line. Scientists do not yet know why.


The tropics is home to the greatest diversity of firefly species. This region is about 1,300 kilometers (800 miles) north and south of the equator.