They are common in wetlands, where they are responsible for marsh gas, and in the digestive tracts of animals such as ruminants and humans, where they are responsible for the methane content of belching in ruminants and flatulence in humans.
Son comúns en zonas pantanosas, onde son responsables da produción do gas dos pantanos, e no tracto dixestivo de animais como os ruminantes e humanos, onde son responsables do contido de metano das flatulencias humanas e arrotos dos ruminantes.