I nearly stepped on this snake a few days ago. It didn’t rattle at me, but that’s not to say it couldn’t have. I tried looking it up, but boy do a lot of California desert snakes look pretty similar to the untrained eye.
The photo was taken at Zzyzx, California, at the edge of the Mojave national preserve. Full-resolution image
Common Gopher snake.
ETA: probably a Pacific gopher snake.
For most of the US, where the poisonous snakes are pit vipers (most - you get coral snakes in places like Florida), the best indicator is probably the shape of the head. Rattlesnakes, water moccasins, etc, have triangular heads with a neck distinctly narrower than the base of the head. Snakes like that gopher snake have rounded heads:
Coloration tends to be a terrible indicator as there is a lot of variance.
As it happens, I had a chance to make a photographic comparison myself a few weeks ago. These two guys were encountered within 100 yards of each other:
Concur, except that in the Zzyzx area ( San Bernadino county ) it should be the Great Basin Gopher Snake - not that it makes much difference. Handsome and relatively mellow population. I’ve never had one in that area try to bite me.
I spent many a spring break in Zzyzx when I was a bio student millions of years ago - neat place :).
I caught a gopher snake outside my house many years ago, and tried to keep it as a pet. It was the meanest snake I’ve ever met - it would strike at me anytime I got near it, and it was big. I finally put on gloves, picked him up and took him to the outskirts of town and released him.
But, I think that snake was an exception - most are supposed to be very docile.
We catch quite a few golpher snakes in So Cal. They are pretty nasty at first but usually calm down withn minutes and become easy to handle. The larger snakes seem more prone to striking has been my experience. Each time you handle them you start from scratch.