Looking After Pet Mice

The hamster may have displaced mice as the most popular of small rodents but, nevertheless, mice are still cute little creatures and have an irresistible appeal for many boys and girls. Pet mice are clean, docile and very adaptable animals, thriving on all sorts of food and often in spite of far from ideal conditions. This is one reason for their popularity in the past, apart from the fact that mice have always been inexpensive.

Young mice of between four to eight weeks of age are the best buy but older animals should not be refused on age alone if they are of a colour you particularly want. Mice are social animals and it is rare even for strange animals to fight viciously. The exception is for old males who have not been kept in groups. In choosing mice, avoid the listless, thin individual, who may be harbouring a disease. The healthy mouse is bright eyed, with a sleek, well-groomed coat, and will move swiftly about the cage.

Single mice will live contentedly and make friendly pets. However, their small size and ability to live together means that several mice can thrive in a single cage. In fact, a group often do better than solitary animals. For parents with several children, this enables each child to have his or her own pet without the nuisance of having several cages about the house.

Sometimes it is said that mice smell. Well, they do and they don’t ! It is the male which gives off the characteristic “mousey” odour. The mouse enthusiast as a rule does not mind the smell and may fail to notice it until someone complains ! The answer is to buy females only. These have little or no smell. For this reason, females should always be bought for family groups if there is no desire to go in for breeding.


The house mouse may be found in all parts of the world. Where the animal has not arrived naturally, it has been carried in ships from almost the first days of seafaring. Keeping mice as pets is almost as old as that of guinea-pigs and rabbits (almost a hundred years) but they have not been written about so much. The National Mouse Club was formed in 1895 and shows for exhibition mice have been held regularly ever since. All sorts of pretty and bright colours have been discovered and bred to a remarkable degree of perfection.


There has been a tendency in the past for mice to be kept in any old box or container. Writers have emphasised how easy it is to keep mice and how they can be kept in wooden boxes, aquariums, even large, wide-necked, glass bottles. Mice are indeed easy to house but, all in all, it is much better to use one of the metal cages sold by pet shops. These are clean and much smarter to have in the house than most improvised or home-made cages. Like hamsters, mice are terrific gnawers and this is the disadvantage of wooden cages.

It is usually possible to obtain cages specially designed for mice but, if not, cages for hamsters are equally suitable. A cage measuring roughly 12in. by 6in. By 6in. High is large enough for a pair of breeding animals; while one as large as 12in. by 12in. By 8in. For as many as six non-breeders. Mice are social animals and groups will live together happily. The above recommendations are minimum sizes, larger cages would naturally be better.

The floor of the cage should be covered with a layer of sawdust to a depth of about tin. Bedding may consist of clean paper, woodwool or hay. The paper can be simply screwed up and dropped into the cage. The mice will soon begin to chew it up. Rather like gerbils, mice love to have “toys” to investigate. Small empty cardboard boxes, tubes from toilet rolls and similar objects will afford them enjoyment. These should be replaced by new objects from time to time since it is the novelty of playthings which keeps them amused. Mice particularly like to run in playwheels. These are often part of the fixtures for many cages but they can be bought separately. There is no need to obtain a large wheel; on the other hand, too small a wheel should be avoided. Playwheels are beneficial since they provide exercise. Solid wheels are superior to the tread-mill type.

Cleaning of the cage should be done regularly once a week. This is desirable not only on hygienic grounds but also to keep down the mousey smell if a male I kept. All old or fouled uneaten food should be dis carded. A corner well away from the nest is often used as a lavatory and this is a help for cleaning. The nest material should not be thrown away unless it is damp or smelly. One of the disadvantages of using paper for nests is that it can become damp more quickly than either hay or woodwool (the latter is to be recommended).


Mice are far from “fussy” in their diet. They can, in fact, thrive quite well on table scraps. The principle to follow is that of giving sufficient food in plenty of variety but not so much that it lies about the cage, uneaten and decaying. It is unnecessary to feed more than once per day except for special titbits which all animals like—even mite.

The staple diet should consist of cereals and grains, such as oats, wheat, mixed bird seed and dried bread. The dried bread can be left overs from the table or end pieces of loaves. If these are baked hard in an oven, they will keep for weeks in a dry atmosphere and the hardness will help to keep the mice’s teeth in shape. Rabbit pellets and the ready mixed diets for hamsters are suitable for mice. Sultanas and currants are usually relished. Small slices of fresh apple and pear, as well as chopped carrots should be given. Little pieces of cheese and bacon rinds are often eagerly accepted. Mice are essentially nibblers, hence feed a little of a variety of foods. “Dinners” can be made on shallow tin lids and it is fascinating to watch the mice nudging each other for tasty pieces. In this way, it is possible to discover which foods they like best. Not all mice have a fondness for the same food.

Water should always be readily available and the most satisfactory method is the adoption of water bottles. Most cages have provision for the fitting of these despite the fact that the bottles have to be bought separately. The bottle should be fixed so that the drinking spout is within easy reach of the mice but not low enough for the tip to make contact with the sawdust. When this happens, the water may be drawn out by capilliary action and be exceedingly messy. It may be necessary to lower the drinking spout temporarily for young mice which have just been weaned.

Mice may be left untended for a short holiday of about a week or so, provided a little thought is given to the problem. Cleaning out of the cage should be left to the last moment. Ample dry food must be given to last the whole period. Pieces of carrot or apple may be given but not too much because these will deteriorate and go sour after a few days. It is better to offer a small quantity which can be quickly eaten. The number of days which elapse before the water bottle needs refilling should be counted. Tithe number is less than the number of days you will be away, buy a second bottle and fix this to the cage as a temporary measure. Be sure that the bottle or bottles are fully filled before you leave. It is much safer, of course, to ask a friendly neighbour or friend to attend to the animals, particularly, if you are to be on holiday for longer than a week.


Mice are so naturally tame that mishandling is rare and mostly accidental. The correct way is to pick up the mouse by the base of the tail, holding him firmly but not too tightly. Never grab him by the tip of the tail since the skin may peel off and cause suffering. Nor, of course, should a mouse be pulled by the tail if he is holding on to some obstacle. His paws should be carefully disengaged. It is simple to hold the animal down gently with one hand while picking him up with the other. An alternative method is to close a hand round his body to form a tube. Just close the fingers gently, do not squeeze. This method is straightforward for a docile mouse but, should he struggle, the temptation is to tighten the fingers, with the possibility of hurting the little animal. With very tame mice the simple extension of the palm of the hand in front of the mouse is sufficient for him to climb onto one’s fingers and even sit in the palm.

Mice are extremely inquisitive and love to be allowed out of their cages for a ramble. A table top makes an ideal playground—more so if it contains fascinating things like cups-and-saucers, plates and ornaments among which to hide. The social instincts can often be seen at these times, for they may play at hide-and-seek and tag, where they follow each other around. Care should be taken that they do not accidentally fall and come to harm. They may injure themselves falling or, if they are not picked up immediately, may scramble down an unsuspected hole in the skirting or floor board. If you have a cat or dog it is wise to put him outside the room while the mice are about.

A lost mouse is upsetting, both to its owner and to the mouse. Except from ripping up the floor boards (which is scarcely practical), one must be patient. In the majority of instances, the mouse will return of his own accord. It is an excellent idea to leave the cage on the floor overnight with the door open, whence the little lost one may be found snug in his nest tilt next morning. Place food in the cage to tempt him to enter; not on the floor outside the cage because he may satisfy his hunger and wander off again. The trick of placing buckets on the floor into which he may tumble works almost as well for mice as for hamsters.


The problem with mice is to prevent them breeding rather than the reverse! This is an exaggeration, of course, for if you wish to have mice solely as pets, then keep only females. However, breeding does give an extra attraction to keeping pets and male and female mice kept together will soon commence raising a family. The female is able to breed from about one month of age although not all females actually produce litters so soon as this. The pregnancy period is about 20 days if the female is not suckling; if she is already raising a family the gestation period is longer, about 7 extra days for a small litter and about 14 days for a large litter. The average litter is five to six young but any number up to ten or even more babies may be produced on occasions. These figures show why it is possible for mice to multiply so rapidly.

Quite the easiest method of breeding is to have a pair of mice in a single cage. These mice produce a succession of litters without calling for special attention. The same food may be fed as one would ordinarily but more of it especially when the babies start to leave the nest and are eating for themselves. It is surprising how much these hungry little fellows can tuck away. The babies are born naked, pink and blind. Within a little while the skin will darken (according to the variety) and a fine covering of hair appears. Almost as soon as the eyes open (which is about the fourteenth day), the young will be foraging for food. The babies run about awkwardly at this age but they mature remarkably quickly. By three weeks, they are miniature adults, bright of eye and as agile as they come. The youngsters should be weaned at this age, for they are now independent of the mother and this gives the female a rest before the arrival of the next litter. Some people advise removal of the male while the female is with young but this is not necessary. He snuggles up with the babies and helps to keep them warm.

Another method of breeding is to run several females with one or two males, removing the females to individual cages when it is obvious that they are pregnant. Pregnancy may be determined by a definite swelling of the female’s tummy. Sometimes the swelling is not obvious should the mother have only two or three young but as most females have more than this number, the swelling is normally unmistakable. Should the cage be large and not too many females are living together, one is not obliged to remove the pregnant animals. Mostly, each mother will make a separate nest, but do not be surprised if eventually the young end up in a single communal nest. Nursing mice are prone to “steal” one another’s babies simply because of an inability to know which are theirs and which are not ! Communal breeding is not recommended when one wishes to be sure of parents of a particular mouse!

Varieties and Exhibiting

There are a large number of varieties and colours of mice, not all of which can be found in pet shops. Nearly everyone knows of the pink-eyed white (albino) mouse but one has to be more knowledgeable to know of the black, blue, chocolate, lilac, silver, champagne, red and cream to name only the basic colours. Many of these have black eyes but some have red eyes. All can be either self (same colour all over) or pied marked, with either small or large patches of white. An interesting series of colours are the tans, where the colour of the back is black, blue, etc., while the belly colour is yellow (tan).

It is not only in colour where mice excel; various forms of coat now exist. There are several kinds of wavy mice, where the coat is of normal length but is wavy or softly marcelled. An angora mouse was discovered not so long ago. In these, the coat is longer than normal and hangs rather loosely on the body. A really fascinating development is the appearance of satin mice, where the coat is shiny and brilliant in colour. Few pet shops are able to stock the tremendous range of colours now available. Many, in fact, do make an attempt to offer a variety of colours and one should make inquiries to locate these shops. The rarer colours never find their way into pet shops. These are bred by breeders who specialise in the uncommon varieties. The names and addresses of these breeders can usually be found in the pages of the fortnightly periodical “Fur and Feather”. This is a periodical for the serious fancier of small livestock.

Shows are held regularly for mice. Some of these are held for local gatherings while others are open for exhibits from all over Britain. The quality of show mice is much superior to ordinary pet shop animals Not so much in health but in colour and size. This is to be expected since breeding mice for shows is a hobby in its own right and has a considerable following. Anyone who is keen can make the change from keeping mice as pets to breeding mice for exhibition. It is a matter of studying the animal more deeply and getting oneself suitably organized. Many shows have classes for pet mice and the beginner is advised to stick to these until he (or she) has learnt the ropes. Exhibitions are grand meeting places and one should not hesitate to visit them. The novice will find that experienced breeders are happy to share their knowledge with anyone who is really interested.

As with hamsters, special show pens are required for exhibiting. These are the “Maxey cage”, so-named after one of the pioneers of the mouse fancy. The dimen sions and paint work of these small cages are rigidly standardized. It is best to buy these cages (they are inexpensive) or at least one, so that exact copies can be made. A mouse shown in an unstandardized cage will almost certainly be disqualified. No special preparations are necessary before showing. If you mice are not in fine condition—clean and healthy—there is no point in entering since these are vital points for show animals.

Always keep the show cage or cages in spick and span condition. Dirty cages are disallowed and then must not be any distinguishing marks whatsoever. Place only dry food, together with new sawdust and a little woodwool or hay in the cage. Do not put in any liquids or food which could spoil the coat of the mouse. Alter a while, the would-be fancier may find it worthwhile to join The National Mouse Club, the name and address of the secretary of which may be found in “Fur and Feather”.

Common Ailments

Mice are hardy little beggars as a rule. This is just as well because they are so small that little can be done to help should they become ill. Their little bodies do not contain large reserves of fat and once they have gone off their food, death follows quickly. The most general symptoms are a dull, listless animal, roughened coat and lack of appetite. Likewise, the most general treatment is warm surroundings (say a room temperature of about 22 degrees centigrade) and the provision of their favourite food. If they cannot be tempted to eat, the situation is usually hopeless.

Mice can withstand coldness provided they have plenty of bedding and are dry. They cannot tolerate dampness for any length of time. Sooner or later, respiratory troubles develop in the form of wheezy and laboured breathing This is not an easy complaint to treat and can persist even after the mice are transferred to dryer surroundings. An excessively dry atmosphere can produce similar symptoms, curiously enough.

Diarrhoea can be a nuisance. Sometimes this is caused by unsuitable food and will disappear almost as soon as it has appeared. In more serious cases, the diarrhoea will persist and the animal becomes thin. This form of diarrhoea is often picked up from wild mice. Death is usually so swift that no treatment is possible. It is contagious and affected mice must be isolated.

If you do have the misfortune to lose a mouse from disease, be sure that the cage is thoroughly disinfected before another animal occupies it. A Lysol solution, made up according to instructions on the bottle, should be applied to the cage by means of a swab of rag. See that the solution runs into the corners and no surfaces are missed. The cage may be air-dried before use.

Injuries may result from too boisterous play or from sharp edges in the cage. Such injuries normally heal rapidly since the mice constantly groom themselves and lick wounds clean. At the first sign of injury, the cage should be inspected for unsuspected sharp edges.

It is sometimes thought that mice harbour fleas and mites but this is not so. In fact, if mice are kept under hygienic conditions they never suffer from these pests. That they can do so cannot be denied but, if they do, it is more a reflection on the conditions in which the mice are kept, rather than upon the mice themselves. Should fleas or mites be detected, use a dusting powder recommended for hamsters or cats. Sprinkle a little on the mice but particularly in the nest. The old nesting material should be burnt and completely replaced by new.

Leave a Comment