Omg! Is My Rat Pregnant?
I have a cage of four females, and they do what is called “mock mating”. It usually happens when one of them is in heat, and that happens every four or five days. Unless you’ve just now put them together, the females would be pregnant way before now. Look at the one that you think may be male. If you’ve got a male that is definitely weaned from it’s mother, you will be able to see their boy bits. Separate them now if he is a real “he”, and get ready to call your vet for more info.
