The sex of a hamster,and pregnancy

Question
I got two dwarf hamsters at the store...in the same cage. One is puffy, and one is skinny,and doesn't have that much fur. They both were about 3 months when i got them. I had to separate them in different cages,because i thought that they were both males, and that the puffier one bit the skinnier one. Bell, the skinnier one, was bleeding because of the bites, and i separated them. Chipmunk, the biter, puffier one, was wild, and kept attacking and whacking Bell in the face. The store did not guarantee the sex, so now i learned that Bell might be a girl. I think so because chipmunk has a whole in his stomach, and Bell doesn't. How do i know for sure?

My other question is that before I separated them, could they have mated, if Bell is a girl? Bell is getting weaker looking, and she is starting to nibble, every so often. She sleeps too often,unless i wake her up. I also noticed that under her, she is producing two small, long, and skinny bumps on each side of her belly. They are about a centimeter thick. Is she pregnant?

Answer
Hi Bella,

you should never buy from a store which cannot guarantee the sex of their animals - this is very bad practice.

The first thing you need to do is find out the sex of both of them.

Please see some of my previous answers about to sex dwarf hamsters.

If one of them is a boy and one is a girl then it is possible that they could have mated before you split them up.

There is not any way of knowing if a female hamster is pregnant, unless she is carrying a lot of babies - and then you can only tell in the last couple of days.

Maybe you should take her to the vets just to be on the safe side.

Let me know how you get on and if you need any more info.

Kind Regards,

Tammy