Though I only saw it in silhouette I knew from shape and size which of our ground squirrels I was seeing as I came down the Saddlehorn Trail. This is a rock squirrel, the one I see least. The trail wound away from it so this was my only good view, I did like that I could put the tops of saguaros behind it for context as it looked out from atop the large granite boulder.
Boolie 
Tiny little shadow critter!