My rat escaped!

Question
I need help! Over the weekend I adopted 2 female rats. They are sisters and about 2 months old. Of the two, Gertrude is a big scaredy rat and she will only come out of her hideaway if I coax her with yummies. Ophelia, on the other hand, is much braver and more eager to explore. She's all over the place and comes running out to greet me whenever I come to play. Well, this morning I was bringing them their morning breakfast, and normally Ophelia would run out to indulge her normally gluttonous nature. However,she didn't this morning. Upon brief inspection, I didn't see her anywhere. I had to leave for work so I couldn't thoroughly search. Is it possible she got out somehow? Can they squeeze through the bars? Can she be hiding under her bedding? If she did get out, will she come back? Also, I have cats. Will she be able to outsmart them and get home? Please help, I am sick with worry for my baby girl.

Answer
 It's possible that she did escape, rats can often squeeze through bars that look too narrow for them to fit through.  Depending on what room they are in, she will likely come back to the cage on her own, though she probably won't be able to get back into it unless the door is open.  If the cage was on a table or something else around 2 feet off the ground, she probably won't jump down on her own though it is possible that she fell or climbed onto something else.

 She'll probably be fine with your cats until you get home, rats are very quick and will usually find a safe place to hide if she is frightened of your cats.  When you get home you should block off the exits to the room the cage is in and do a thorough search for her, keeping an eye and an ear out for movement and sounds of her scurrying around.  Rats can fit into anything their head can fit through, often through holes as small as a quarter.  Keep this in mind when you are looking for her.  They usually move along walls and avoid being out in the open, and will gravitate towards any food sources if they can't get back to their cage.  They usually are most active at night, and evenings and nights would be the best time to hear where she is or even see her.

 You may want to try putting her cage on the floor next to a wall, she probably will come back to it when she gets hungry.

 If you are unable to find her after a thorough search, you may have to invest in a live trap to catch her.  They can be purchased from pet stores and farm supply stores.  It's best to leave the trap unset with food in it and you can check it nightly to see if any of the food is gone.  This will get her to not be scared of the trap, and teach her to come into it to get food.  You can then set the trap, so it will close when she goes inside, and hopefully it will catch her.

 Well I hope she's all right and you find her soon!  Good luck!