[Humphrey Furball]

Can you hear any "crunching" sounds when the hamster is in his nest/house? Often they like to eat in private where they feel secure, more so when they are getting used to a new environment. If needs be, you could try switching lights out in the evening, as if you are going to bed, and just sitting in silence; you may hear some munching activity if the ham thinks he is alone! If you are worried about the teeth though, the vet is a good idea, just to make sure there are no issues; are his teeth an orangy yellow colour? (this is the normal healthy colour for hamster teeth). Lastly, if you have some scales, you could weigh the hamster a couple of times a week, just to keep an eye on him (I weigh mine by putting him in his carrier, then weighing the whole thing, putting him back in his cage, and weighing the carrier; obviously one minus the other = weight of the hammie). Hope he's OK