Keeping Mice as Pets Content from the guide to life, the universe and everything

Keeping Mice as Pets

A pet mouse

When people think of mice they generally imagine wild mice that like to creep into the house during winter to make noise and mess. Fortunately, not all mice are like that. The 'not so wild' sort, known as the domestic or fancy mouse, are specifically bred to make excellent pets.

Domestic mice come in a variety of colours - blacks, greys, whites and mixtures, with different coloured tails and eyes. They are nocturnal - sleep in the day but are very active in the evening and at night. The average life expectancy of a mouse is 18 months to two years.

Buying a Mouse

Mice can be found in pets shops - where they are usually extremely cheap - or may be given away free by other mice owners who have too many to keep.

Mice are extremely small when newborn, but are not usually available in shops for purchase until they have developed into juveniles or adults.

When choosing a mouse it's best to go for one that looks healthy. A mouse that runs around happily and has shiny fur and bright eyes is a better choice than a mouse with dirty-looking fur who huddles nervously in a corner1. Even non-experts should be able to work out which mice look well and which don't.


To pick a mouse up, lift it either gently by the base of the tail and place it on the palm of the hand, or pick its body up using one or two hands. Do not squeeze too tightly and ensure that it seems comfortable, with feet supported. Mice can bite although not too severely, and usually only when they've been provoked. Mice that are used to being handled often, especially from a very young age, almost never bite. Never dangle the mouse by its tail; this might be appear fun, but will not be enjoyed by the mouse.


Mouse should be kept in a cage to prevent it getting lost or stood on, as well as preventing a mess and it running loose throughout the house.

The three main options are glass, plastic or metal/wire cages, with advantages and disadvantages to them all. Wooden cages are not a good idea, as the mouse could chew through it and escape.

  • Glass cages - they are easy to clean, but can break or crack easily.

  • Plastic cages - they are easy to clean, but can occasionally become deformed or the mouse can chew through it.

  • Metal/wire cages - these can get too hot in the sun if the mouse is outside, and if they are made of mesh it is hard to see the mouse. Horizontal bars must be narrow so the mouse is not able to squeeze through and escape. Hamster cages often have bars that are too wide for housing mice securely.

For DIY enthusiasts, then cages can be homemade but they would have to be made of non-varnished wood, non-toxic glue and have no sharp edges. Buying cages from a shop is simpler but will generally cost a lot more than the mouse did!

A cage should be tall enough so a mouse can stand up on hind legs without hitting the ceiling. The area should depend on how many mice the cage is intended for - two mice need about 60cm x 30cm. One mouse will need less room, and three will need more. Obviously choose a cage that has air holes or an opening so the mouse will not suffocate!

It is best to keep the mouse inside the house, so it will not get too hot or cold. Except for tropical countries, it will be too cold to leave the mouse's cage outside especially during winter, but equally it can also be too hot in the summer months. Avoid leaving the cage in very draughty areas, in direct sunlight or in a place with extremes of temperature.


Mice need some sort of bedding on the floor of their cage. Wood shavings are probably best, as they are very absorbent. Make sure these wood shavings are chemical free to prevent any ingestion of toxins which will harm the mouse. Shredded paper can also be used, although sometimes ink on the paper can be bad for the mouse. Straw is another possibility. As well as this, mice need a separate dark area (preferably away from the rest of the cage, via a ramp for example) where they can sleep. They will make their own nests - this is a great activity, as it keeps them busy. Paper towel is ideal for making good nests; place one or two folded sheets in the cage, and the mouse will tear it into an appropriate shape for sleeping.

Cages will rapidly become smelly. Small cages need to be cleaned about every two or three days. Larger cages may be able to go a week without being cleaned, but the smell will probably become unbearable, particularly with male mice. When cleaning a cage, remove all old bedding and nest material, rinse the cage and replace with new clean bedding. If the cage is particularly smelly, scrub the cage with some form of detergent and rinse well afterwards.

Food and Water

Mice need to eat some hard food so their teeth don't become too long. Special hard pellets for mice are ideal for this, along with grains and seeds, commercial 'mice and rat mix' that are available from pet shops. Linseed, oats, lentils and popping corn are a favourite too. Mice love grey sunflower seeds, but these should be given sparingly as they are rather fattening. As well as that, mice need fresh fruit and vegetables such as apples or carrots. Mice are often depicted eating cheese but it is not an ideal treat for mice as it can cause dietary upsets, although some mice enjoy a small amount as an occasional treat without any problems.

The first time a mouse is given a new type of food, they may not eat much of it in the first two days or so. A slow change in diet is recommended to prevent any dietary problems. If they suffer no ill effects, they should start to eat more of that food over the next few days.

It is essential that mice get clean fresh water every day. This can be distributed either in a small bowl or dish, or in a special water container with a tube and nozzle. Bowls and dishes are quite easily knocked over, and the mouse may put bedding inside the dish, or decide that's a great place to urinate. 'Feeder bottles' are easily attached to wire cages (it's a lot harder with plastic or glass) and are probably easier for the mouse to drink out of. However, the mouse can push bedding up the nozzle blocking it up.


If the mouse is sick, their coat and eyes will become duller, they won't run around much and they might not eat much food. Many people are reluctant to take mice to vets as the cost of a single vet consultation can cost as much as twenty mice! A common problem for mice are tumours and available treatment can be limited even in specialist exotic hospitals. Something the mouse ate or drank may have made it sick (diarrhoea or funny-coloured droppings may confirm this). Often a thorough cage-clean, fresh food and water and some special care can help a sick mouse. More serious problems will probably need veterinary attention - it is cruel to leave the mouse to either get better by itself or die.

Multiple Mice

Two male mice together will usually fight although, an exception to this is when the mice have been reared together and never separated from each other. However, two or more female mice together will probably get along quite well. It is best to have at least two mice as they are generally considered to be 'social creatures' and prefer having company.

If an adult male and female are housed together, they will mate and the average litter size is between six and 14 baby mice. The gestation period of mice is three weeks. Mothers should be left alone when giving birth and for a short time afterwards otherwise they might become agitated.

Oddly, mother mice might eat their young, or the baby mice might eat their mother. Male parents should be kept away, as they are very likely to eat the babies. Mice eating each other can occur due to stress, for example when overcrowding happens in a cage, or the mother is disturbed, post labour.

Fun for Mice

Mice need exercise and entertainment so they don't become bored. Putting a running wheel inside their cage is a great idea. Wheels with a solid inner surface are better for the mouse's feet than wheels with a non-solid inner surface, such as slats or wire spokes. Some form of tube (for example the centre of a toilet roll is ideal) with holes cut in it is fun for the mouse. A maze can be made out of blocks, Lego™ or Duplo™ for the mouse to run through to find food.

Thinking of getting a pet?

Thinking of getting a pet? Rats, guinea pigs, cats, ferrets, rabbits, hamsters and gerbils all make excellent pets as well as mice. Or perhaps something more exotic such as a corn snake or an Axolotl takes your interest!

Clubs and Societies

1This can sometimes be misleading as mice, especially young ones, do tend to sleep a lot; not every huddled-up mouse is ill.

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