Mice as Pets

Choosing and Caring for a Pet Mouse

White mouse in basket
ivanmateev / Getty Images

A quick glimpse of a group of pet mice playing and you'll realize they can be quite entertaining pets. They are a bit skittish and harder to handle than some of the larger rodents such as rats, but they can become quite tame, and will learn to take food from the hand and allow themselves to be handled if started at a young age.

Mice are quite ideal as small pets that are entertaining to watch, easy to care for, and make very few demands on their owners.

  • Scientific name: Mus musculus
  • Lifespan: 1 1/2 to 3 years
  • Size: 5 to 7 inches (including tail), up to 2 ounces
  • Difficulty of care: Beginner, as mice are easy to care for and make excellent pets for children and adults

Mouse Behavior and Temperament

Mice are nocturnal and very social, and they are best kept in groups. A pair of females is the easiest arrangement, although larger groups are fine if you provide the cage space.

Pairs of males should be avoided unless they are litter mates, never separated, and given a large enough cage that they can have their own space; unfamiliar males are very likely to fight. Keeping males and females together should be avoided unless you want lots of mice in a short amount of time.

Most mice will become quite tame given time, patience, and perhaps a little bribery. At first, allow the mice time to become accustomed to their new environment. Once the mice are calm, start spending more time near their cage and quietly talk to the mice to get them used to your voice.

As the mice become comfortable or curious with your presence, start offering some favorite tidbits (try millet or sunflower seeds) by hand, and once the mice are taking treats from your hands, they may start walking on your hands, or you can start trying to pick them up.

When picking up a mouse, it is best to try scooping it up by cupping your hand under the mouse, but do not squeeze or tightly grasp the mouse's body. If holding a skittish mouse, you can try holding the base of the tail with one hand while supporting the mouse's body in the palm of your other hand to prevent the mouse from jumping off your hand and possibly injuring itself.

If you hold further down toward the tip of the tail, you may break the tail off or the skin may come off the tail.

Be careful when holding mice, as a relatively short fall can cause injuries. It is best to hold the mouse just above your lap or some other soft surface in case it falls or jumps.

If you are going to allow your mouse time outside the cage, you will need to mouse-proof the room. Ideally, keeping them contained in a large, shallow plastic storage box, small wading pool, or some other confined space is the best option for keeping the mice safe and sound.

Housing the Mouse

The size of the cage you will need depends on how many mice you will keep together. For a pair or small group of females, a 2-foot square cage is an ample space. Mice will appreciate a cage with multiple levels, as they do like to climb, and it should be fairly tall.

Glass aquariums and wire cages are the best types of cages for mice. Aquariums will need a tight-fitting mesh lid and lots of furnishing supplied for climbing and playing. It is also important to remember that ammonia and other fumes will build up faster in an aquarium or plastic sided cage than in a wire cage.

Wire cages with horizontal bars are nice because they provide lots of climbing opportunity on the sides of the cage, and it is easier to affix furnishings, platforms, and toys to the sides of the cage. Make sure the bars are not too narrowly spaced so that the mice can escape (or get stuck trying to escape) and that the doors are placed to allow easy access to the entire cage for when you need to catch the mice. Avoid using cages with wire mesh floors—solid flooring is a lot easier on the mice's feet.

The modular plastic cages meant for hamsters are actually well suited to the mouse size and activity level but are difficult to clean, are sometimes poorly ventilated, and a determined mouse could chew right through the plastic.

The cage should be placed where the mice will have lots of human contact to make taming easier. It should be out of drafts, away from direct sunlight and out of reach of other household pets.

Mice need lots of opportunities to play and exercise. Mice seem to universally love running on wheels, so add a wheel or some tunnels made from plastic plumbing pipes sections or paper towel/toilet paper tubes. Other toys mice enjoy include:

  • Wood blocks and houses
  • Small cardboard boxes
  • Ladders
  • Cotton ropes
  • Egg cartons (paper only)
  • Small willow balls

Depending on the size of the cage, it may need to be cleaned quite frequently, especially glass or plastic sided cages that allow ammonia and odors to build up more quickly. It is best not to wait until you can smell a problem because it will be quite overwhelming to the mice by then.

The mice do, however, need to mark their territory, and if their cage is completely disinfected too frequently, they may be distressed. A good compromise is to leave a bit of the old shavings or litter in the cage at each cleaning so their scent remains, and only do a thorough scrubbing and disinfecting when absolutely necessary.

Specific Substrate and Nesting Needs

A deep layer of aspen shavings or some other suitable substrate should be provided in the cage. Avoid cedar and pine shavings due to the strong volatile oils released from these woods (especially cedar).

In addition, nesting material should be provided. Strips of facial tissue or soft paper towel will happily be shredded by mice and make nice nesting material. Hay can also be used.

A nest box should be provided and can be store bought or homemade. Small cardboard boxes are fine, although they will be shredded over time and need to be replaced fairly frequently. Clay flower pots, either with holes cut in them or placed on their sides, can also be used, as can PVC plumbing pieces you can find at the hardware store. The nest material should be cleaned out only every month or two as needed (more frequent changes may be too disruptive).

Food and Water

Mice can be fed a commercially prepared complete diet; a rodent mix or hamster diet is acceptable. Pellets are available for mice and are completely balanced, but this is a monotonous diet. Grain and seed-based loose mixes provide more interest to the mice and will probably be more readily eaten. Your mice may just pick out their favorite bits and leave the rest, leading to an imbalanced diet.

The basic diet can be supplemented with small quantities of fresh fruits and vegetable such as greens, apples, and carrots. Watch for diarrhea, though, and if a particular food item does cause diarrhea, discontinue feeding it. Sunflower seeds are a favorite treat of many mice but are quite fatty so should be limited.

Cooked pasta and whole grain bread or crackers can also be given, maybe with a tiny amount of peanut butter as a special treat. Commercial treat sticks make a good treat, but only very occasionally, as they are often quite sweet. Avoid feeding junk foods such as candy and potato chips, and never feed chocolate, as it is toxic to mice and other small pets. For water, a gravity fed water bottle with a dispenser is preferred, as it can't tip and keeps the water clean. A shallow food bowl of ceramic or porcelain is the best choice, as they are difficult to tip, won't get chewed up, and they are easy to clean.

Common Health Problems

Tumors are common in mice, and unfortunately are usually malignant. If you notice a lump or swelling or other symptoms such as lethargy or weight loss, these are signs of a tumor. Most tumors can be surgically removed, but are likely to recur.

Perhaps the most serious health condition in mice, as well as other rodents, is wet tail. This is a gastrointestinal ailment caused by bacteria in the digestive tract. It can progress quickly and may be fatal if left untreated. Symptoms include diarrhea, lethargy, lack of appetite, and difficulty walking. Wet tail must be treated with antibiotics from a veterinarian.

Purchasing Your Mouse

When picking out your mouse, look for an alert animal with smooth, clean coats and pink, clean skin on the ears and tail. The eyes and nose should be free of discharge, and the mouth and anal areas should be clean and dry. Their breathing will be relatively fast, but should not be labored or noisy. Check the cage as well; it should be clean and the droppings should be formed.

Look for a pet store that separates males and females at a young age (good breeders will do this). Mice can reproduce by about 6 to 8 weeks of age, although this is very stressful on the female and should be avoided.

Similar Pet to the Mouse

If you're not sure whether a mouse (or mice) is the pet for you, there are some similar animals you may want to consider:

Otherwise, check out other small animals that could be your next pet.