Is there something wrong with my hamster?

Question
Dear Kelly,

I got a hamster about a month and a week ago. She seemed perfectly
normal at first, but after about one or two weeks went by, I began to
notice this swelling thing on her bottom. It changes size and shape every
day, and I'm worried that it's wet tail or constipation. Help!

Sincerely, Gwen

Answer
Well, I'm not Kelly but I'll give it my best shot.  :)

Wet tail's one main characteristic is runny, profuse diarrhea.  If you don't notice diarrhea, it probably isn't wet tail.  (And if it was wet tail, you'd notice.  That's how it got it's name.  The runny mess sticks to the fur around their bottom, giving them a constantly "wet tail" appearance.)

It sounds to me like what you are observing are the testes of a male hamster.  :)  Many people are baffled by the swelling under the tail of the "female" hamster.  The testes will move and appear to change size or shape depending on how you are holding him (and how he feels at the moment).  This is how many pet store employees think they are selling a female hamster, when in fact they are selling a male:  They will pick the hamster up and let it dangle either by its scruff (ouch!) or under it's forelegs.  The skin is then pulled up towards the hamster's head, which sucks the testes in for a moment - making the hamster look as if it doesn't have testes at all.

But, of course, I can't see the hamster, and it could also be something much less benign.

If you are worried that your hamster is ill, you should seek veterinary advice.

Here is a link where you may see the differences between the male hamster and the female hamster:

http://www.petwebsite.com/sexing.htm