Bioluminescence is the production of cold light by living organisms. It is thought to be the end product of oxidation of luciferans (organic compounds). Why animals bioluminesce is uncertain. Some groups bioluminesce by shedding their tentacles or releasing clouds of fluid when they are disturbed (e.g., siphonophores, ctenophores, and ostracods). Organisms may also use bioluminescence as a decoy to distract predators, for communication, or to attract prey (e.g., siphonophores such as Muggiaea, pictured here).