if you look closely, the brown specles are in focus with the snake which means they are not on the lens (the snake is one plain, the lens is another, and the CCD of the camera is another, depending on what is in or out of focus will tell you where the dirt is in the system). Those specs look to be on the snake itself.
And, IMO, i'd ask for an image with some kind of scale (a quarter or a ruler or the snake in a scale) the floor boards compared to the snake is what would make me wonder.