Since they are both female, and both unspayed (assuming), you will most likely know when they are in heat, as they will jump around and flick their ears a lot, and a LOT of mounting will be done. Female rats mount eachother quite frequently, so if you see this don't be alarmed. Just wanted to give you a heads up.

Also, glad to see you got her a friend! If you didn't quarantine the newbie you'll want to watch them both very closely the next couple of days to look for signs of illness, such as lethargy, sneezing, red staining around the eyes and nose, lack of appetite etc.

Now that winter is here, make sure they have something nice and cozy to snuggle in. If you don't have one already, rat sleeping bags are great at keeping the nudies warm. If you have any questions about them feel free to ask. I bred rats for close to 10 years, and know pretty much all there is to know!

They are both very darling. It's cute to see a standard ear next to a dumbo.