A firefly is a small flying beetle that produces flashes of light from its abdomen, creating a magical sight on warm summer evenings. These insects, also called lightning bugs, generate their glow through a chemical reaction in their bodies called bioluminescence. The light uses very little energy and produces almost no heat, which scientists call “cold light.”

Fireflies flash their lights in specific patterns to communicate with each other, especially during mating season. Each species has its own unique flashing rhythm, like a secret code. Males fly around flashing their pattern, while females sit in grass or on plants and flash back if they're interested.

Despite their name, fireflies aren't flies at all, but beetles with soft, leathery wing covers. They live in meadows, forests, and backyards across much of the world, though they're becoming less common as natural habitats disappear. The larvae, called glowworms, also produce light and live in the soil or rotting wood, hunting snails and slugs.

Catching fireflies in a jar on a summer night is a childhood tradition in many places, though they should always be released so they can continue their evening activities.