Reptile & Amphibian Forums

I just got an Eastern Ribbon Snake and I'm holding it today when i notice that it has some rather curious head movements once it settles down. It will move its head back and forth along a lateral line (as opposed to in an arc). I mean, it's not swinging its head back and forth like it's looking for anything. Its just moving its head back and forth, like its watching a tiny ping pong game but doesn't want to bend its neck. No tongue action, either, by the way.
So - I was (as the topic would indicate) just curious as to some opinions on this behavior. I'm not worried about it in any shape or form, just curious. I've never seen that before in any snakes I've ever owned (he's my forth), so I'm wondering a) what that could mean, b) why he'd be doing it, and c) if anybody else has seen that before.

I have a ribbon snake who does the same thing. He's about four years old and I've had him for about two. He does that when he's watching me play the computer or watching my cat watch him. And he's done it the whole time I've had him. -Shrugs-