I took the day off yesterday and went on a bike ride along the C&O Canal. It was a nice way to spend the Earth Day. One of the places I passed by was Nolands Ferry where the remains of this old wall is alongside the path.
When I first saw this head sticking out of a gap between the blocks in the wall, I thought it was of a dead black rat snake* (Elaphe obsoleta). It was totally motionless when I approached it with my camera. After a few shots, I was getting ready to leave when I turned to take one last look and noticed that it had moved further into the gap. So it was alive. Then I saw its forked tongue flickering in and out of its mouth. Whenever I lifted the camera up to my eye, however, the tongue would disappear, only to return after I lowered it again. I was not to have a more exciting picture.
*Identified by Butch Norden of the Maryland DNR.