Rats and Mice


The domesticated rat is descended from an albino strain of the brown rat, which arrived in New Zealand in the nineteenth century as a stowaway on European trading ships. Today, there are many varieties of domestic rat to choose from as companions.

For many children, a rat is an ideal companion. They are active and intelligent and, with gentle handling and care, are very tame. Rats enjoy human companionship, and live for about three to four years.

In some overseas countries rats are very popular, especially with residents of high-rise accommodation where it is difficult to have a cat or a dog.

A Note to Parents

Please bear in mind that your children may become bored with their animal after a few months. You will then become responsible for all the animals' daily needs.


Prepare for your rats before you bring them home. Have ready the cage, food and drink containers, gnawing log, bedding and, of course, a food supply. Moving house is traumatic for any animal, but by preparing in advance your rats can move straight into a secure and comfortable environment.


Rats are very easy to handle and soon become tame, provided they are carefully and gently handled. They will bite if handled too quickly or too roughly. A rat should not be picked up by its tail. Instead, slowly pick it up by cradling or cupping your hands, and then place the animal on a flat surface with a little food. Alternatively, put a hand gently around its chest and lift it onto the palm of your other hand for support. Gently stroke its back. Repeat this every day, as often as you can, and soon you will have a little friend that trusts you.

Social Grouping

Two male or two female rats of the same litter, housed together before puberty, will usually live quite amicably in one large cage. It is unfair to keep rats singly, as they are social animals and appreciate company.


Living quarters should be designed to give the sort of conditions which most closely resemble the animal's natural way of life, with access to tunnels for hiding in and materials like straw and shavings for warmth and nest-making.

Small mammals should be housed in cages where they may be viewed from the front, not from the top, as this is less stressful for them. Do not get a cage that is too small for its occupants. A minimum size cage for two adult rats would be one metre long by 60 cm wide by 60 cm high, but a bigger cage is strongly recommended. It is possible to adapt a rabbit hutch by substituting a smaller gauge of wire so that it is escape-proof. If you decide to build your own cage, it should be designed so as to facilitate easy cleaning. A pull-out metal tray on the bottom is one suggestion.

Rats are inquisitive creatures and they like to see out of their cages but (as with mice) they need privacy too, so some sort of covered shelter and nesting box should be provided within the cage.

Because rats require a higher ambient temperature than rabbits or guinea pigs, they are not suitable for keeping in outdoor accommodation in winter.


A suitable 'playground' outside the cage, or incorporated as part of it, is beneficial, not only for the rats but also for their owners who will enjoy watching the antics of the animals. Toys (such as plastic tubes, small boxes and driftwood) will provide many hours of amusement.

Something to gnaw

Rodents require material to gnaw, in order to keep their incisors sharp and worn to the proper length. A small log or a bone should always be available for this purpose, or your rat will soon gnaw its way out of its cage.


Like mice, rats need a lining to their cage that can be composed of sawdust, peat, woodchips or wood shavings, with a layer of shredded paper on top for nesting. Avoid cedar and pine sawdust or any treated wood as these contain oils and preservatives that may be poisonous to rats. Shredded paper should be plain white paper, tissues or paper towels, but never newspaper as the printing ink can be poisonous.


Rats may well pick a corner of the cage for urination, and cleaning out daily is a simple matter. Bedding should be changed two or three times a week, and cages should be washed and disinfected each week. The rats should not be returned to their cage until the cage is thoroughly dry.


The dietary requirements for rats are very similar to those for mice, but of course they eat considerably more. Pellet food provides good, basic nutrition and is available from most pet shops. Rats may also enjoy oats or wheat, green vegetables, apples and carrots. Generally speaking, an adult rat requires 15-30 g of pellets (or equivalent) each day. Always use gnaw-proof containers for food.


A rat will drink 20-45 ml of water each day, so it is important that water is available continuously from drinking bottles. These should be cleaned thoroughly at least once a week with a bottlebrush and sterilised occasionally.

Thorough rinsing afterwards is essential to avoid any chance of toxic residue.


To prevent unwanted offspring the SPCA strongly recommends either having male rats desexed or only keeping same-sex rats together. Rats are prolific breeders, and SPCA's often receive the unwanted offspring. If your rat becomes unexpectedly pregnant, bear the following in mind.

Female rats carry their young for 20-22 days and give birth to a litter averaging eight to 11 youngsters. The baby rats weigh approximately four to six grams at birth and are born with their eyes closed. These open in approximately 14-17 days and the baby rats are weaned at five to six weeks of age, reaching puberty at nine weeks.

A male and female rat paired together throughout their breeding life could produce a litter every four to five weeks! As the size of an average litter is between eight and 11, it is obvious that the breeding of rats is not recommended.


Prevention is better than cure. Purchase healthy animals and maintain good husbandry by providing adequate ventilation, clean cage conditions, sound diet and regular vet checks.

Respiratory diseases: Coughs, snuffles or pneumonia are caused by a variety of viruses, bacteria and other organisms. The most common and persistent is chronic respiratory disease. Signs include sneezing, weight loss, runny nose, snuffling and 'chattering'.

If you notice any of the above symptoms - or any lumps, hair loss, diarrhoea, excessive water drinking or loss of appetite - consult your veterinarian.

Note: Do not be alarmed if your rat vocalises during play or has a red discharge from the eyes. This can be normal for rats, but if it concerns you, contact your veterinarian for advice.



A Note For Parents

Your children may become bored with their pets after a few months. You will then become responsible for all their daily needs. Please bear this in mind.

General Information

Mice have been part of the human environment for around 10,000 years. They originated in the grain producing areas of northern Asia, gradually spreading to all parts of the world. Today's fancy mouse is a direct descendant of the house mouse but comes in white and a variety of whole and mixed colours. Their average life span is 2 - 3 years.

Mice are social creatures and it is not kind to keep one mouse in isolation. Two or three females are a practical arrangement. Many male mice will fight after the age of puberty i.e. 6 weeks.

Mice can be visually enchanting creatures and quite comical to watch during their play activity. A word of warning: It is difficult to eradicate their somewhat musty odour and extreme cleanliness is absolutely essential if the odour is to remain within bounds. Some consider that female mice are less likely to offend than males.

Because mice require a higher ambient temperature than rabbits or guinea pigs, they are not suitable for keeping outdoors in winter.

Prepare for your mice before you bring them home. Have ready their cage, food and drink containers, gnawing log, bedding and of course, a food supply. Moving house is traumatic for any pet, but by preparing in advance your mice can move straight into a secure and comfortable environment.


Living quarters should be designed to give the sort of conditions which most closely resemble the animals natural way of life, with access to tunnels for hiding in and materials like straw and shavings for warmth and nest-making. Toilet roll holders make easily replaceable tunnels.

Small mammals should be housed in cages where they may be viewed from the front, not from the top, as this is less stressful for them. Mice do not need expensive housing, but the following features are important:

Hardwood cage with an escape-proof wire mesh front

Hinged lid to allow easy access to the mice and to facilitate cleaning

A small dark nesting box for a gallery, located close to the lid of the cage, with a ramp for the mice to reach it. This is important, as mice will suffer great stress if such a retreat is not available.

Alternatively, purpose-made cages are available in pet shops. They sell reasonably and contain a nesting or sleeping box and living quarters of a type suitable for their welfare, but do make sure the cage is of sufficient size to leave room for the mice as well as the toys! A suitable cage size for two mice is 60cm x 30cm x 25cm.


Mice generally use one special corner for toilet purposes, so clean this daily and replace with clean, dry litter. Cages should be thoroughly washed and disinfected every 3 - 4 weeks and dried before returning the mice to them. Mice cannot tolerate damp conditions so a spare cage is useful at this time. Do not disturb the nest unless necessary as too frequent cleaning of this area can cause stress by disturbing the natural scent that the animal has created in its environment.


Sawdust, peat, wood chippings /shavings all make suitable lining for the cage. Shredded paper is necessary for nesting material. Cotton wool is also appreciated for this purpose. Do not use newspaper as the print can be poisonous. Renew bedding several times each week to minimize odours and lessen the risk of disease.


Mice are inquisitive and provision should be made in their cage for exercise toys. Miniature ladders, ropes, ferris wheels and perhaps a cotton reel, plus a small bark covered log for gnawing, will all serve to provide a stimulating environment. Consider building a multi-storied mouse cage to give more opportunity for exercise.


Mice thrive on pellet food (obtainable from pet shops) as a staple ration, with some raw vegetables and fruit, such as carrot, swede, celery and apple for variety. Fresh hay and water are also necessary daily requirements. The water should be given ad lib from drinking bottles, which the mice will quickly learn to drink from. A mouse will normally drink 3 - 7 ml per day.

A little canary or parrot seed, wheat, oats, rolled oats or stale wholemeal bread, also pleases them. They sometimes enjoy a little grass too.

Empty, wash and refill the food and water dishes daily as they can easily become contaminated. Mouse food is best fed in heavy-duty pottery or gnaw-proof containers or by using food hoppers.

Remember to provide your mice with a piece of hardwood to gnaw upon, thus preventing their continually growing teeth from becoming too long.


Mice should be lifted by taking the tail firmly, very close to the base, while supporting the body with the other hand.  Never lift or hang a mouse by its tail.


The female mouse (or doe as she is called) carries her young for 19-21 days, the average litter size being between 6-14. The baby mice are helpless when born and it is important that the nest is not disturbed at this time. The youngsters open their eyes 12 - 14 days later. They are weaned around 19 - 21 days and reach puberty at 6 weeks. Female mice come into heat every 4 - 5 days and unless she is separate from the male (or buck) mouse before giving birth she may mate again almost immediately. This means that she will give birth to her second litter shortly after the first litter has been weaned.

The young should be sexed at 5 weeks of age and segregated. Male mice cannot usually be kept together without fighting after the age of puberty and as mixed pairs breed so rapidly you can see how very easy it would be for your mouse family to expand at an enormous rate. Therefore, breeding is not recommended.


Mice do not recover easily if they become ill, so try to prevent illness by maintaining a high standard of care. Changes in temperature can cause respiratory infections such as bronchitis and pneumonia.

Intestinal complaints can result from sour food and/or unclean containers.

Scratching around the head and ears, cuts, scabs and bald spots are signs of skin mites. 

Mice groom themselves provided their cage is kept clean, but daily handling helps to keep animals tame and enables a check to be kept on their health.