Before you get pet rats you must have a safe home for them to come home to. Don't make the mistake of thinking you can merely put them in a box or aquarium. They will eat through most boxes, and aquariums are generally too small and prone to condensation for more than a brief stay. Plan and build a large, well-thought-out environment. It will pay off in reduced cleanup time, more enjoyable interaction and happier, healthier rats.
Rats need food, water, a safe place to sleep, and room to exercise and amuse themselves. All that requires space. No rat, any more than we humans, wants to spend his entire life in a small enclosure, so plan to make his cage as large as conveniently possible. That way you can include space to explore and help stave off boredom. Rats are highly social, so make room for at least two rats. If possible, build a play area large enough for you to sit in with them. It will add to the fun you and your rats enjoy together.
People build rat cages out of many materials and prefabricated things – like plastic boxes, aquariums and even modified bookcases or other furniture. While many of these work well when large and altered to provide adequate ventilation, the best cages for rats are made of wire. Wire provides good ventilation and a climbing surface as well as visibility for both you and your rats. However, wire can prove hard on delicate rat feet, so include a solid floor and use wire only for top and sides. Solid plastic or metal floors work best for easy cleanup, but surface-laminated wood or wood faced with tiles will wipe clean and will keep odors and mess to a minimum.
Location and Creature Comforts
Since rats are most active at night, consider putting their cage somewhere that allows them to play as noisily as they like without disturbing your sleep. Conversely, they will need a quiet place to rest when you are up and active. Ideally, they would have a room of their own. But if space is at a premium in your house, a compromise would be a quiet corner of the living room or another room that your family frequents in the evenings, when your rats will start to become active. Rats need a space within their cages to retreat to when frightened or tired. A cage should never be kept in cold, drafty rooms or in areas with too much light or heat. Rats have about the same temperature comfort zones that humans do.
After dealing with the important physical considerations for the cage, turn your attention to the fun stuff. Rats are curious, so give them plenty of things to do and places to go. Empty boxes, PVC pipes, ladders, climbing ropes, hammocks, clean logs and rocks all make worthy additions to a rat gymnasium and recreation center. When choosing exercise wheels, know that one 11 inches in diameter and solidly floored on one side and around the rim works best. Wire wheels aren't safe for rats, who tend to get their tails and feet caught in them. Never put rats in exercise balls, as they can seriously overheat inside one, and can't stop when tired.
If you have small children or other pets -- especially dogs or cats -- do not leave rats unsupervised or in unsecured enclosures where they are vulnerable to harm. Avoid putting a rat cage in a kitchen or dining room, where sanitation is a major consideration. Rats are very clean little creatures, but they can carry illnesses and diseases common to humans.