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Hamster Suddenly Gains Weight

What would make a hamster suddenly gain weight?

By Karen Rosenthal, DVM, DABVP
Posted: November 27, 2009, 5 a.m. EST

Q: My Chinese dwarf hamster, Cloe, is almost 3 years old. Cloe lived with another hamster until about six weeks ago when the other one died. Cloe has been getting really fat quickly over the past week or two. I think it is too late for her to be pregnant, and my other hamster was probably female. Her stomach is so big that sometimes it is hard for her to get up. I felt it, and half of it is sort of squishy but the other half is not. Does she need a veterinarian?

A: There are two general reasons for the weight gain: Cloe may be reacting to the loss of your other hamster or Cloe has a medical condition that should be seen by a veterinarian.

Is Cloe “mourning” for her friend, which is causing the weight gain? We cannot say. But possibly the other hamster prevented Cloe from overeating; without the friend, Cloe is eating more and gaining weight. Or without the friend, Cloe is less active. With no other hamster for Cloe to chase or vice-versa, Cloe is exercising less and the weight is being put on. Sort of like a “cage potato.”

If the weight gain isn’t due to behavior changes, this could be a medical condition that needs attention. Cloe is getting up in there in years for a hamster, and older hamsters are prone to cancers. This could be a cancer in Cloe’s abdomen. Only your veterinarian can tell you if that is true and if it can be treated.

If you don’t want to immediately take Cloe to the veterinarian, try a weight-loss regimen and see if there is a change. Restrict the amount of food that Cloe gets to only what is necessary for one hamster. Make sure there is a wheel or some other form of exercise that Cloe can get. If after a short time Cloe doesn’t change in appearance or if she gets worse, please find a veterinarian who will see your hamster.

See all of Dr. Rosenthal's Critter Q&A articles>>

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Hamster Suddenly Gains Weight

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Reader Comments
Hello Sam, The best advice we can offer is to take your hamster to a veterinarian who regularly treats hamsters so he or she can examine your pet to find out what's going on. Hamsters are only pregnant for 15 ot 18 days, so it doesn't seem like she could be pregnant if she's been alone for three months. Wishing a speedy recovery for your pet!
Marylou, Irvine, CA
Posted: 8/2/2012 11:23:07 AM
Hello. My Russian hamster has been rapidly gaining weight. We think she might be pregnant because she has two lumps about the size of a ping pong ball. Her nipples are suddenly noticeable and when we feel her stomach we feel lumps. When we hold her we put her on her back and she cant get up. We just adopted her from PetSmart about three months ago, but she was in the cage with a female at the store. We also think that she might be eating her bedding, she has the soft stuff kinda like soft cardboard. We first noticed her getting bigger about two weeks ago. Please help, I'm really worried! Also, we do not know how old she was when we adopted her.
Sam, Leesburg, VA
Posted: 8/1/2012 2:13:41 PM
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