My Rat Sophie

Question
Hi,
I am concerned about two things with my rat.
My life is getting busier so I have less time to spend with my rat Sophie. I got her when she was roughly a month old and have now had her for two months. I am worried that she is getting bored and lonely while i am working. Is she still young enough to accept a new cagemate without problems? And can her new cagemate be from a different litter as long as they are the same gender?
Also I woke up this morning and my Sophies feet were as cold as ice and her tail had a slight blue tint  to it? I am worried that she is getting sick because the rest of her body is warm. I tried seeing if she was just cold from the fan I keep running in my room so the room does not get hot. Her feet warmed up but her tail still has a blueish tint to it?  Should I be worried? If so what kind of illness am i dealing with?

I would really appreaciate your help cause I am not sure what to do and I only wants whats best for my little Sophie.

Answer
I am quite certain that Sophie is lonely.  Rats are extremely social creatures and need to be paired no matter how much human company they get.  In fact, good rat breeders will never allow people to adopt only one.  So DO get her a female cagemate as soon as possible.  It is NEVER too late to introduce 2 female rats to each other no matter what their age, but younger is always easier and Sophie is still a baby (with males, it's a different story especially if they are mature).  

Just be sure you are patient with their introduction.  You should initially keep them in 2 cages side by side so they can see and smell each other for the first few days.  Next, you should introduce them in a neutral area like a bathtub or enclosed space that is unfamiliar to Sophie.  Do this a couple of times.  Expect that they may "fight" on and off...that is normal as they are trying to establish dominance one over the other.  Next, let each rat explore the other one's cage alone (so put Sophie in the new rat's cage and vice versa) for a little while.  Repeat this a few times over a few days.  Finally, when you think they are ready, put them together in the new rat's cage and again, expect some fighting.  The fighting will go on until one had established dominance over the other and then there should be peace.  Don't interfere with the fighting unless you notice it's very violent or there is blood (that probably won't happen).

As far as the blue tail, it is possible there might be a circulation problem, but usually the feet would also be blue.  Sophie is actually quite young for such a problem but it's not unheard of.  For your own peace of mind, I suggest you do take her to a vet, but make sure the vet is an exotic vet and has specific experience with rats.  If you need help finding an exotic vet, reply to me with your zip code and I can probably help you.