lol I fell for that the last time I started a snake thread. (I think it was one I started.) I remember thinking what the hell is a trouser snake so I did a google image search and I had the safe search off.....boy was I surprised.
It is a Texas rat snake (sometimes called a chicken snake locally). It is a non-venomous but pretty aggressive snake abundant in Texas. I do animal physiology research, and the prof I work with is a snake guru. He discovered that the pits on the face of a snake are thermal pits for finding suitable habitats. He said its a rat snake, so it is a rat snake!