Mice — Environment


Cages and all facilities used to secure mice must be constructed and maintained to reduce the risk of injury and attack by predators.

Mice may be kept in intensive conditions provided the following conditions are met:

    • A minimum floor space of 500cm2 should be provided per pair or trio plus litter
    • A minimum cage height of 12.5cm
    • The diet composition and quantities of feed must be recorded
    • A nesting and hiding area must be provided
    • A high level of hygiene and cleanliness must be kept at all times
    • Environmental enrichment must be provided to enable natural behaviours
    • Faeces and urine accumulations must be removed twice a week
    • Normal diurnal pattern of lighting must be provided with periods of dark
    • Opportunities for appropriate exercise must be provided
    • Air must be of acceptable quality with respect to dust, chemicals and smells
    • All mice must be observed standing and moving during daily inspections.


The environmental requirements of small mammals including mice are complex and must be considered carefully when providing them with a suitable living environment. Mice should never be housed with other species and their cage or nesting place should be regarded as the animals’ home or domain and should be disturbed as little as possible. Mice should not be housed in the same room as other animals as they are prey for most other species. There are many different cage styles available for mice but it is important to ensure that cages meet the standards required for safety, security, ease of cleaning, animal comfort and allow student observation. Suitable cages can usually be purchased at pet stores or unused aquariums with a wire mesh lid are appropriate enclosures.


Movement and Exercise

Everyday activities including walking to food and water, climbing, jumping and playing with other mice gives mice adequate exercise. If exercise equipment is available they usually enjoy using it. Running wheels are usually very well utilized and are recommended to increase exercise and reduce boredom. Elevated boxes and tubes made of either cardboard or polycarbonate make excellent exercise areas.



Natural lighting is always preferred however artificial light with the full range of spectral colours, 45–60 lux is acceptable. Cages should be kept out of direct sunlight. Shelter should also be provided within the cage to allow the mice to avoid light. Students should be able to observe that mice will seek darkness if it is available to them. There should be 12-hour periods of both light and darkness.



Bedding used in mice cages should always be highly absorbent dust free, splinter-free, non-toxic, non-edible and not contaminated with pesticides or chemicals. Suggested bedding is sawdust, wood shavings, clean shredded paper, soft cardboard, rice hulls or absorbent paper pellets.



Preferred temperature is 18–22°C. Large fluctuations in temperature should be avoided.



Ensure that there is always good natural ventilation provided for mice.



Mice must always be housed indoors.



Cages should be cleaned regularly, at least twice weekly, then washed in disinfectant and thoroughly dried. New bedding should be supplied and old bedding disposed of in a suitable manner.



Easily shredded materials must be provided. Shredded paper, straw, soft cardboard, paper towels or cotton fibre are suitable. Cotton wool should not be used as it can wrap around the legs of young mice and cause injury. Shredded paper can also cause fine paper cuts in very young un-haired pups.