The desert moss Syntrichia caninervis is a promising candidate for Mars colonization thanks to its extreme ability to tolerate harsh conditions lethal to most life forms. The moss is well known for its ability to tolerate drought conditions, but researchers now report that it can also survive freezing temperatures as low as 196 C, high levels of gamma radiation, and simulated Martian conditions involving these three stressors combined. In all cases, prior dehydration seemed to help the plants cope.