My hamster has recently died while sleeping in his corner, by no means was he neglected as he always had his food and water and his cage was kept clean. But suddenly he had just passed away not too long ago and saying that, I got him about six months ago and he wasn't even two years old. He used to have two other female hamsters in his cage which the two of them passed away due to age, but after they passed away, the male one became more aggressive that being why I didn't play with him as much as before. He was kept in a small corner in the living room where he could see light and people. This morning I was going to give him some more water and shook his cage a bit to wake him up but he didn't move, I got worried and tried shaking it some more but he simply didn't move from the corner where he always sleeps in. He passed away I don't know when since I've been in the hospital this whole week and he couldn't have died due to diabetes or being obese since he had to get up and climb the cage in order to reach his food not to mention he has his wheel. Any theories on why he may had died?