Do snakes yawn??

Sometimes my snake'll just be sliding a around and all of a sudden open his mouth, like a yawn.
This doesn't happen frequently, just on occasion. Should I be worried?
(also, my apologies if this is in the wrong forum)

Mine yawns all the time. Though I can't say for certain that its a yawn like us humans do.

They yawn to re-adjust their jaws - especially after eating but Valentine will occasionally randomly yawn.

Snakes "yawn" for multiple reason. Just like mentioned most common is to readjust their jaws. Some do it to have a little stretch after being in their hides for a while. They also do it if they can't breath properly (RIs , stuck scales and other reason) but it would be a frequent yawn not just once in a while in that case.