Behavior Normal?

Question
Hello,
My Syrian hamster is about 1 year old. She has been healthy and active since she was born. She liked to run and always wanted to get out of her cage (which was a 10 gallon aquarium) and run in her ball. I felt that her cage was too small for her active lifestyle, so I purchased a Large 50 Gallon tank for her and built her multiple levels out of wood. At first, she loved it and ran all over in it. But lately, her behavior has changed. She has gained a lot of weight, eating excessively. She sleeps almost all day and doesnt run in her wheel. When I put her in her ball, she either walks around or falls asleep in it. Since my guinea pig had cancer, I knew what to feel for, but did not feel anything abnormal. The only other abnormal thing I noticed is that her eyes are bulging more than usual. She has been like this for a couple of weeks now and I am concerned. It is winter and colder than usual and I have read that they can begin to hibernate in this situation, so I thought this might be normal. I am still concerned though. Is this behavior normal? If not, should I see a vet? Thank you for your help!
Sincerely,
Christopher

Answer
Hi Christopher,

    The being less active, sleeping more and the weight gain (which is because of her being less active) are generally normal signs of aging. This process generally starts around the 1 year mark.
    I would suggest cutting back on her food a little bit to help with the weight gain by only giving her half of what you would normally give. Hopefully she will take off some weight before she gets too big and in to more serious health problems.
    The bulging eyes could be from an infection( which could also cause her to be less active), and I would definitely suggest that she be seen by a vet for that.
    If you have anymore questions, please write again.

Thank you for writing and best of luck!