If there is life on Mars, it certainly hasn’t jumped out and mugged for the Mars rovers’ cameras like many people had hoped. And most scientists agree it probably won’t. In fact, any critters that lurk on the red planet today would almost certainly be part of an underground organization that has defied long odds and the harsh realities of a very unfriendly world. So why all the excitement last week over once soggy rocks at Meridiani Planum?