is my hammie a boy or pregnant?!?

Question
hi there,
      I bought my hamster last week at 10 weeks old, The pet shop owner sold her to us as a girl although they said they were not 100% sure as she diddnt like to be turned over. i have always had male hamsters but am finding it hard to tell. She looks like a male in the fact she has a rounded bottom but does not have any visabil testicals. She has been getting a little tubby round the belly altough she is compleatly obsessed with running on her wheel! She has hoarded all her food and compleatly changed her bed and made a nest in the courner and She seems quite twitchy. When i cleaned her cage out she peed blood. Which i am pretty worried about although she seems happy and livley. Do you think shes pregnant or does the blood indicate she has had some sort of miscarrige! Please Help!!! im confused!

Answer
Hi Alice,

Well, it does sound as if your hamster is a female.  And the behaviors you're describing (larger belly, nest in the corner) indicate that she may in face be pregnant.  It's almost always difficult to tell.  The typical gestation period is around 16 days, so just keep paying close attention to her.  If she hasn't given birth about 10-11 (depending on the exact day you got her from the pet shop - just count 16 days from then, to be safe) days from now, she is not pregnant.  As far as the bleeding - Female hamsters don't have menstrual cycles, but once or twice in their life they may suffer from a small amount of vaginal bleeding. This bleeding is only very minor "spotting" and occurs for only a day or two. The cause for this is not known but it does not seem to be due to any illness.

Excessive or prolonged vaginal bleeding can be due to a uterine infection or other problem and should be investigated by a vet.

However, you may want to consult your vet about the bleeding anyway, to rule out any serious problems.

If you have any other questions, please feel free to ask.