Rats are very social and intelligent pets. They do best in pairs. Two females can reliably live together while males can do well together only if introduced young. Don't keep males and females together as rats are prolific breeders, producing up to 20 babies in one litter. The typical lifespan of a pet rat is 2-3 years.
Common signs that something may be wrong with your rat include sneezing, lethargy, weight loss, dull eyes, open wounds, diarrhea, difficulty breathing, and lumps. Rats are susceptible to external parasites such as lice. If you notice any of the former symptoms or parasites, contact your veterinarian right away.
Pelleted or block-type diets are available for rats, and are formulated to be nutritionally complete. Choose a rat block that is low in fat and calories, and has soy meal high on the ingredient list rather than corn. While rat blocks should make the basic diet, a variety of fresh foods can be used to supplement the diet, which will aid in keeping rats healthy and prevent boredom with the pelleted diet. Packaged loose mixes are also available, but rats tend to pick out their favorite bits from the mix, which may mean they're not eating a balanced diet.
Try small amounts of fruits and vegetables such as peas, carrots, apples, bananas, whole grain pastas and bread, brown rice, yogurt, and occasionally low fat cooked meat, mealworms, cheese, seeds, and nuts. Treats such as plain dog biscuits can also be given. It is important to keep rats on a high-fiber, low-fat diet, so limit higher fat foods such as cheese, seeds, and nuts to very special occasions. Do not feed rats sugary foods such as candy, chocolate, or junk food.
Heavy ceramic food dishes are best for feeding your rat as they are sturdy, don't tip over too easily, and they're simple to clean. A water bottle with a sipper tube can be used for water. Make sure a supply of fresh, clean water is always available.
A large wire cage with a solid bottom is best to house your rat. A tall cage with ramps and platforms is ideal for providing room for multiple rats. At minimum, a cage with 12 x 24 inches (2 square feet) of floor space is okay for two smaller rats, as long as the cage is tall and you provide shelves and/or hammocks for extra space. Overall, larger is always better. Large aquariums are okay, but don't provide good ventilation (and must be cleaned more often).
Avoid cages with wire flooring as spending time on wire flooring has been linked to a condition called bumble foot where the feet become red, swollen, and bumpy. Also look for wire that is a fine grid (½ x ½ inch maximum). Your best bet is to look for cages that have plastic or wood shelving, or you can modify cages using melamine-covered boards to make your own easy-to-clean shelves.
The cage should ideally be placed in a relatively quiet location, but still near the social activity in the home. Rats are nocturnal, so choose a location where it's fairly quiet during the day. Placing the cage on a table or stand will help the rats feel more secure. The cage should not be placed in direct sunlight or in drafty locations. Limit access to the cage by other household pets as a rat will understandably feel threatened by a cat or dog hovering outside the cage.
For bedding, avoid cedar and pine wood shavings as these woods can be harmful to rats. Carefresh or aspen (or other hardwood) shavings are best. There are many other good pet bedding and litter options available these days that are very absorbent, not dusty, and safe for small pets. Some are pelleted and not very comfortable for rats to play and sleep in, so some people use the pelleted products (which are usually very absorbent) under a layer of softer loose bedding.
You'll also want to provide some nesting material which the rats can shred and use to line their nest box. Paper (no ink), plain tissues, and paper towels all work well.
Usually the rats will chose a bathroom location in one area of the cage. Heavily soiled litter should be scooped out daily, and more litter added if needed. Thoroughly clean the cage with warm, soapy water once a week.
A nest box should be provided, either store-bought or homemade. A cardboard box makes a perfectly acceptable nest box, but plan to replace it often. Other possibilities include a flowerpot or jar turned on its side, or a section of PVC drain pipe (perhaps cover one end). Store-bought boxes are good too, but keep in mind that wooden ones can be hard to clean if they get urine on them, and the plastic ones might get chewed up fairly quickly.
Rats have sharp little nails, and for your comfort you may want to trim them when playing with your rats. Check them every one to two months. Nail trimming is not difficult, except that your rat will probably object and try to squirm away. You can use a pair of human nail clippers and just trim a tiny bit off the tip and avoid the pink part (quick) inside the nail as this is a blood vessel and nerve. If you do happen to nick the blood vessel, a little cornstarch or Kwik Stop applied to the nail tip should stop any bleeding.
Check the teeth occasionally to make sure they're not getting overgrown. Make sure you provide lots of chewing opportunities to keep their teeth healthy.
Rats are friendly and curious by nature, but you'll need to spend some time getting them used to handling. Start by hand feeding them small treats. When they are comfortable accepting treats, pick them up one at a time — one hand supporting the bottom, the other over the back. Once hand-tamed, many rats will become comfortable enough to sit on your lap or shoulder.
Rats love to climb, and will make good use of ladders, ropes, hammocks, tunnels, and platforms. Blocks of wood for chewing, cardboard tubes, and toys designed for ferrets or parrots are good choices. Look for rope and wood toys as many plastic toys can't stand up to chewing by a determined rat. Simple items like large cardboard mailing tubes, crumpled paper, paper bags, and cardboard boxes can also make wonderful toys. Rotate the toys on a regular basis so the rats don't become bored.
Some rats like to run on exercise wheels (and some will never try). If you get one, be sure to choose the solid type without wire rungs. A rat’s feet or tail can get caught in the rungs or the supports on which the wheel is suspended.
Exercise and playtime outside the cage is a must for the smart, active rat. Make sure that the area you allow your rats out in is secure and rat-proofed, since rats will chew on just about anything they can get their teeth on. Make sure electrical wires are out of reach or encased in plastic tubing and that your pets cannot access anything that is toxic, including poisonous plants. Rats tend to leave scent marks as they roam in the form of little drops of urine. The odor is not offensive, but you may want to cover furniture with a throw while they are out. They will also do this on their owners, so be prepared!