Oh dear, never a dull moment up here in the East Mountains. I discovered this snake waiting for me at my back door this morning.
I didn't see it when I stepped out the door – it’s actually lying on the threshold of the full-length window NEXT to the door, thank goodness - but one of my dogs went into a whimpering, curtseying dance at the threshold and refused to go out.
Then I heard the rattle ... a sound I'd never heard before, but made my hair stand on end.
The dogs and I ran away; I came back with the camera.
I assume from the sound that this is a rattlesnake? It was about 2 feet long, but only an inch or so in diameter. I’m guessing from the size that if it’s a rattlesnake, it must be a young one.
The weird thing is, the head isn't as strongly wedge-shaped as other pit vipers I've seen (in Belize, not here). You can see its head better in this closer photo, taken from the safety of indoors:
Soooo … is there another kind of snake in New Mexico that makes a warning rattle? Did I actually hear a rattle, or was it just a hiss? It sounded like a rattle, according to my ancient rat brain.
If it is a juvenile rattlesnake, I’ve just read that they’re considered the most dangerous:
Rattlesnakes are born with fully functioning fangs capable of injecting venom and can regulate the amount of venom they inject when biting. Generally they deliver a full dose of venom to their prey, but may deliver less venom or none at all when biting defensively. A frightened or injured snake may not exercise such control. Young snakes are to be considered more dangerous, as they have less control over the amount of venom they inject.  A young rattlesnake will often simply inject all its venom, which might be a lethal dose, depending on the bitten animal.
(1) "Venomous Snakes". National Institute for Occupational Health and Safety Topics. Centers for Disease Control.
Designer, kNotes for kNitters
Sandia Park, NM
UPDATE: Thanks to the friendly local folks on the Albuquerque City Data Forum, I now believe that this is NOT a rattlesnake, but a bullsnake, which resembles it.
Bullsnakes may vibrate tail when alarm, which may sound like a rattlesnake, also makes a hissing noise. However, they may from time to time get hit over the head with a hoe for doing too effective a job of acting like a rattlesnake.
I feel better already, especially since I didn’t kill it.