Texas Rat Snake

Imagine my horror and fear as I went to get my mail and saw a snake nearby the mailbox. I'm talking about 20 feet, but still, a wild snake 20 feet away is WAY too close for me.
I thought it had been run over by a car because it was at the edge of the road and it wasn't moving. My terror that it could be dangerous kept me from getting closer, so I looked and looked and burned it into my memory as best I could.
When I got back I told N I saw a big honking snake that was "this big" 16-20 inches with spots on it's back. He said, "Oh, that sounds like a Diamondback Rattlesnake." I freaked out and spent a good deal of time looking up snake pictures on the internet to find out that it wasn't a rattler at all, I thought it was a King Snake. I put aside the thought until now and looked some more to find lo-and-behold it appeared to be a juvenile Texas Rat Snake.

I thank my lucky stars for three things.
1) They are not venomous!
2) It was not moving!
3) It wasn't full grown!

Full grown rat snakes are generally between 42 and 72 inches and are about a foot long when hatched. They are tan/brown snakes, when young, that have darker spots down their back roughly in the shape of a tanned hide (I've also seen the term "saddle") with smaller spots of the same color going down the sides. These spots generally fade with age and the snakes themselves can appear anywhere on the spectrum from brown to yellow.
They're heads are grayer than the rest of their bodies (usually with a arrow shaped marking on them) and appear slightly wider than their body. That's just something I read, I didn't get close enough to be able to tell.
When it shakes its tail it can sound almost like a rattlesnake, even though they have no rattles. While these are highly aggressive snakes they can't really break the skin when they bite and are constrictors by nature. They are prized for being good at what they do, eating and killing rodents. They are great climbers and will go up trees and into attics in search of prey.
They live primarily in Texas and can be found pretty much anywhere that happens to have bountiful munchies.