This is a great shot! Look at that tail bristle. I can practically hear this squirrel chattering at the photographer. I like the strong diagonal composition. It really works to add tension to a shot which could have easily been just a cutesy animal snap. There is lots of fine detail in the texture of the concrete and the squirrels fur. I would say it also meets the criteria because it is not every day one gets this close to wildlife, even city critters like squirrels. Kudos!
Cute. Sharp and a nice angle for both the concrete lines and the little guy's pose. Very good. I especially like the detail on his toes. Sharp little claws!
Sorry, I don't see how it meets the challenge. Maybe you happened to be somewhere and you got this shot, but if that's the challenge criterion, couldn't ANY picture meet the challenge?