A team of Canadian, Scottish and U.S. researchers says they have discovered traces of methane in meteorites from Mars -- a possible clue in the search for life on the Red Planet.

The researchers examined samples from six Martian meteorites that had fallen to Earth. The team crushed the rocks and then analyzed the gases that emerged using a mass spectrometer.

The meteorites were found to contain gases similar to the composition of the Martian atmosphere; they also contained methane.

Mars has a thin atmosphere that causes the planet's surface to be bombarded by radiation, making it inhospitable to life. But these findings raise the possibility that there may be more hospitable settings within the planet's crust.

On Earth, methane is produced by animals and microbes, known as methanogens. The research team says the most likely source of methane on Mars is the reaction between water and common igneous, iron and magnesium-rich minerals.

They also say it's possible that methane is, or has been, used as a food source by rudimentary forms of life beneath the planet’s surface. On Earth, there are single-cell microbes called methanotrophs that consume methane to create energy.

While there is now evidence of water on Mars, the question of whether the planet also contained methane has been a source of controversy, says Matthew Izawa, from the Department of Earth Sciences at Western in London, Ont.

"We have demonstrated that there is a source of methane within the Martian crust but it remains to be seen if such subsurface methane is the source of the Martian methane that was detected," he said in a statement.

Sean McMahon, a Yale University postdoctoral associate in the Department of Geology and Geophysics, says his team's findings will likely be used by astrobiologists in experiments aimed at understanding whether life could survive below the surface of Mars today.

He added that the team's approach may prove helpful in future Mars rover experiments.

"Even if Martian methane does not directly feed microbes, it may signal the presence of a warm, wet, chemically reactive environment where life could thrive," McMahon said.