You definitely can!! I’ve had mixed results with mine…some rats love to run in it, some love to sleep in it, and others look at it like a wall hanging. If you do decide to put a wheel in your cage, make sure that it isn’t a hamster wheel–they’re too small for rats. Also, it’s important that it’s not made out of mesh because a rat’s feet and tail can get caught. The best wheel for a rat is called the Wodent Wheel, and they come in several sizes. Hit up google and see what you can find.