Garden Helpers

We had an encounter yesterday that required us to re-familiarize ourselves with good and bad snakes.  Working along the house by the low tunnel, I spied something next to a rock.  Better safe than sorry, I summoned the experts (Myron, dad and Bama!)  For quite some time, the head was all we could see.  Here are a couple of clues that were extremely helpful:
1. Pupils round or elliptical? (round, nonvenomous; the exception is the coral snake)
2. Heat sensing pit between eyes and nostrils? (no, nonvenomous)

Then it came out of the hole.  And kept coming...
3.  The head, while triangular, is not broad.

4. Tail stays close to the ground, and no rattler.

After measuring the space that the snake HAD occupied (hey, it may not be poisonous, but it is a constrictor), we estimate the length at just over 5' 3".  This bull snake is a welcome predator among the many we see around the farm, including road runners.