Coming to think of it, I will take mine to the vet in a few days anyways... I'll ask him if he knows anything about that behavior, maybe it's really just harmless yawning or maybe something else.
I'll let you know!! :tort:
Okay so like I have no scientific proof for this...
But mine does that too, has always been doing that since I got him (he was 8 months old).
The time when he tends to do it the most is in the morning after waking up and in the evening before going to sleep... Just a weird guess but he might...