Firefly is the name commonly given to several kinds of beetles that glow like sparks of fire in the dark. Fireflies live in warm and tropical countries. They eat pollen and other foods during the day. When nerve stimulations release another chemical, inorganic pyrophosphate, the bond breaks and the reaction produces cold light.
Bioluminescence is the emission of light from living organisms without generating heat.
Light is produced by oxidation of luciferin which is catalysed by the enzyme luciferase. This phenomenon is found in many organisms like fish, fireflies, worms, cnidarians, ctenophores, molluscs, fungus, dinoflagellates, bacteria and others.