What are the implications of the recent report in Sciencexpress 15 January 2009 (Mumma et al.: Strong release of methane on Mars in northern summer 2003) that active and local sources of methane exist on our neighbor planet? The authors suggest three possible explanations: Production of methane in the magma of the planet, ‘serpentinization’ of basalt, or production by psycrophilic methanogenic bacteria. How do other pieces of information – like the seasonality of the methane occurrence and the local enrichment of ‘phyllosilicates’ – fit the different models?