Hypsiglena chlorophaea Desert Nightsnake
Some other names for this species:
Desert Night Snake, Nightsnake
Subspecies I've seen:
H. c. chlorophaea
Sonoran Nightsnake
H. c. deserticola
Northern Desert Nightsnake
H. c. loreala
Mesa Verde Nightsnake
Hypsiglena chlorophaea chlorophaea Sonoran Nightsnake
Sedona, Coconino County, ArizonaAugust 14, 2004
Sonoran Nightsnake (Hypsiglena chlorophaea chlorophaea) Sonoran Nightsnake (Hypsiglena chlorophaea chlorophaea)
This cute little snake is common throughout much of the western U.S., but I had somehow managed to avoid seeing one for my entire life up to this point. My wife and I were hiking with our friends John and Brenda McCaffrey in the gorgeous red rock country near their Sedona home. I lifted an old dried hunk of yucca and saw a scorpion crouched below. Everyone came over to see the scorpion when John spotted this little snake trying to discreetly glide back into the hunk of yucca I was holding up.

Then while I was trying to coax the snake into sitting still for a photo, Brenda saw a rock move. Only it wasn't a rock, it was a rock lobster! Well, actually it was a short-horned lizard. So it all goes to show that you should be sure to stop and smell the scorpions. Or something like that.

Sedona, Yavapai County, ArizonaApril 6, 2005
Sonoran Nightsnake (Hypsiglena chlorophaea chlorophaea)
Night snakes, being (surprise!) nocturnal, are not usually seen on the surface by the light of the day. This one was under a flat sandstone rock, and only reluctantly stayed on the surface for a few photos.
Yuma County, ArizonaMay 19, 2015
Sonoran Nightsnake (Hypsiglena chlorophaea chlorophaea)
This is possibly the least-exciting nocturnal desert snake, but for some reason I still haven't seen many of them. It's hard to believe that ten years have gone by since I first saw this subspecies, but I think that is indeed the case.
Hypsiglena chlorophaea deserticola Northern Desert Nightsnake
Anza-Borrego Desert State Park, San Diego County, CaliforniaJuly 2, 2006
Northern Desert Nightsnake (Hypsiglena chlorophaea deserticola)
After two nights of road-cruising for snakes in which I had failed to see a single live snake, my luck began to turn when I found a small nightsnake crossing the road. Within an hour or so I also saw two young glossy snakes. Not a very good night for snakes at Anza-Borrego, but a big improvement over none at all.

The taxonomy of this species has been revised numerous times in recent years. I don't think the dust has settled yet, but I'm using the taxonomy described in SSAR names, so I'm calling it H. c. deserticola. Until recently the U.S. nightsnakes were considered part of H. torquata, but that species has now been more narrowly defined such that it exists only in Mexico.

Hypsiglena chlorophaea loreala Mesa Verde Nightsnake
Grand Staircase-Escalante National Monument, Garfield County, UtahJuly 21, 2017
Mesa Verde Nightsnake (Hypsiglena chlorophaea loreala)
This subspecies is distinguished from the others by the presence of one additional scale between the front of the eye and the nostril. Isn't it obvious?
Grand Staircase-Escalante National Monument, Garfield County, UtahJuly 25, 2017
Mesa Verde Nightsnake (Hypsiglena chlorophaea loreala)
So far this is the only Hypsiglena I've ever seen that held still in a serpentine arrangement. Usually when observed/disturbed they squirm rapidly out of the way, or get all bunched up.
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