Life on Mars

Just a short comment: should we find life on Mars it would be far stranger than anything we envisage now.

And I do not mean monsters with tentacles (that's very normal), nor the fact that this life may be based on silicon not carbon (very unlikely, but still just chemistry).
The life would be `self restrained'. And that would be really strange. Of course the most probable solution is that there is NO life on Mars. Then again there is nothing strange.

Where does this prediction come from? Well, consider Earth. What is the probability that a spaceship would land on Earth and fail to discover life? pretty much close to zero. Earth life has infiltrated every niche, from abysses of the oceans to the volcanic pits. Deserts of Sahara are full of life.
Earth life even managed to invade meteorites coming down from space.

With the signs of life-friendly (at least at some time) environments on Mars, if we assume that life there would be similar in principle to ours, it is strange that the planet would not be just as inhabited as Earth is. Of course this might be just some micro(nano)organisms or some other forms, but why are they not everywhere? The `principle' I have in mind is replication, because this is the motor force for the ultimate conquest of Earth by living organisms.

So, if there is life on Mars and if it has not conquered the whole planet, then it must be very strange: refraining from the `go forth and multiply' rule.