The evidence so far predicts that Mars is now sadly dead. The ratios of gases in its thin atmosphere are not consistent with a living planet (no oxygen, and the

The evidence so far predicts that Mars is now sadly dead. The ratios of gases in its thin atmosphere are not consistent with a living planet (no oxygen, and the seasonal methane is probably geological). Ancient Martian life was probably identical to Earth's, due to similar conditions, chemistry and exchange of genetic information between the two planets (and Venus, in addition to life from other solar systems via comets). In the rocks we should find fossils eventually with our current rovers.