The composition of an atmosphere can reveal whether a planet is habitable or maybe even inhabited. The presence of methane in an atmosphere is one such marker of habitability or habitancy. There are multiple published reports of methane in the Martian atmosphere. Various conclusions about the spatial and temporal variability of methane, and its formation, may be drawn from these measurements. Measurements planned for the future and some not yet planned can improve the characterization of atmospheric methane and its implications for the habitability and habitancy of Mars.