My partner and I brought home a 10 week old hamster on Saturday morning, and we left him alone for a while to get used to his new home. In the late evening, after wandering around his cage for a while he seemed to have suddenly stopped moving, he was just laying on his side. So we got him out of the cage and he was completely limp, we stroked him for a good 30-40 seconds before he opened his eyes then jumped to life. After this he has seemed absolutely fine. I have read that a change in environment and temperature can cause hibernation, but I would have always thought it meant if they were too cold. Saturday night was hot if anything, do you think this and the stress of moving home could have caused hibernation behaviour? We have been trying to keep him as cool as possible ever since and he seems perfectly happy, although I am now concerned as he sometimes seems to be falling asleep outside of his bed in different areas of the cage. Do you think it would have been hibernation or something more serious? Also, do you have any tips to encourage him to run on his wheel as he has not worked this out yet and tries to climb on the top! I am worried that he will not get enough exercise.