Brainstem programming

So I was walking along the path in the garden, and suddenly I stopped.  Not that I intended to stop; my body just stopped of its own accord.  A moment of puzzlement, followed by understanding.  Ah, that would be because of the snake in my way.

Quite a big snake, maybe 18 inches long, brown, not much in the way of markings, no "V" on the head, no obvious zig-zag pattern.  Aha, says I, a grass snake.  I noticed that it had a very short tail.  You can't see it in the picture, but it was only about 3 or 4 inches long, quite short in relation to the rest of the snake.   I happened to have my camera with me, and took a picture.

I wandered inside to look up what kind of a grass snake it was.  I had trouble making a match.  Grass snakes have a small number of large scales on the head.  Well, mine didn't, not really; it had a lot of small scales.  Grass snakes have round pupils, and vipers have a slit.  This difference is definitive.  I couldn't see the eyes of my snake, but I enlarged the photo, and could just about make out the right eye.  Vertical slitty.  Oh.

So I look up vipers, and can't find anything that matches my snake.  But apparently the asp viper has markings, but on the male they are indistinct, or at least, less distinct that on the female.   The asp viper often has a "V" on the head.... but not necessarily.  And a notably short tail.  Ah.  Perhaps I have a male asp viper.   The bite, I read, is painful, and spreads, and is fatal in humans if untreated, in about 4% of cases.  I left it alone, and it was gone by the time I got back to it.

And the new lesson learnt today?   Just because it doesn't have a "V" on its head, doesn't mean it's not a viper.