Definitely not a moccasin. The head is all wrong. I might be willing to agree on the black racer, but the young ones I've seen about this size (basing size on the rubble and debris) usually have more grey and more defined blotches in the pattern. Still, it could very well be one that has started darkening early... Yeah, I'll go with Juvie Racer that needs to lay off of the tanning booth. It's the only thing that really comes to mind looking at him.

Its an Eastern Garter Snake. They're harmless and nonvenomous.

Well, now you all have me completely confused but yet totally facinated about snakes. I have read all 22 pages of postings on this forum and it seems that Rat Snakes are by far the most common backyard snakes (and maybe garter snakes which I was already familiar with). So how do you tell the difference between a Black Rat and a Gray Rat and why do you think this is a Black Rat and not an Intergrade Black/Gray. I also saw another snake the other day, about 4 feet long and just solid black, so I am assuming Black Rat Snake (no camera handy). So, although I'm interested in learning more, I don't think I am ready to try to catch one. I know that they have their proper place in our eco-system and I am happy to leave them be outside as long as they aren't dangerous to me or my little dog (my fish and frogs in my fishpond, however, may not be as lucky?) This looks like a very interesting hobby. We also had a snake a couple of years ago that everytime we saw him he would dive into the fishpond. I haven't seen him lately. So, if I see a snake in the yard, like the Rat Snake, is it more likely he lives here or more likely he's just passing through?

Probably an Eastern Garter Snake ... their color varies wildly, but the black head and stripes along the body with sort of "checkerboard" patterns between the stripes is one variant. They are not venomous, but they will bite and also release a VERY SMELLY fluid if you handle them. http://www.paherps.com/herps/snakes/garter_snake/