Last night, my hamster Sausage went in his hamster wheel (its one of the rotastak ones which sits outside the cage). There is a long tube which connects the wheel to the rest of the cage. Sausage kept running in the wheel for a few seconds, and coming along the tube very cautiously as if he was scared of something, and he was making a weird clicking/teeth chattering sounding noise. I've heard him make that noise before but I can't remember when, and he didn't do it as much as he did last night! In the end I took the tube away so he could come out of the wheel quicker and he did come out eventually - when I turned the light off! Do you know what the clicking noise is - I'm guessing it was a scared noise but I don't know why he would have been scared!