The Mouse Fancy

Angela King
Photos by Eric Jukes
From the Jan/Feb 1996 Rat & Mouse Gazette


Fancy mice are bred with the aim of attaining standards specified by fanciers organizations such as the National Mouse Club in England. They hold shows just like rat or dog shows where mice are judged according to those standards. There are many different color varieties, as well as coat types. Included in these are Satin (the coat has a high gloss, almost metallic iridescent finish best seen on lighter varieties), Longhaired and Astrex (wavy coat with curly whiskers, ideally with the coat in rosettes like the Astrex cavy). Fancy mice are members of the species Mus Musculus, being descended from the House Mouse (also Mus Musculus) along with the laboratory mouse and ordinary pet mouse. However, selective breeding has produced fancy mice that look quite different from their pet and laboratory counterparts. Besides the range of colors and coat types (some of which were first found in laboratory mice, such as the Satin coat mutation), fancy mice are larger than other mice (other things being equal, size is considered a virtue in competitions) and have longer tails and larger ears. The overall effect is to make the fancy mouse far prettier than any of its close relatives. They can have other advantages over ordinary mice, too. Show mice need to be in peak condition as well as being in good health, so, normally, fanciers would only breed from robust, healthy mice; there is no room in the stud for weak or sickly animals. There is a large hereditary element to the functioning of the immune system, so fancy mice should be healthier than ordinary mice on the basis of generations of selective breeding. Because fancy mice need to accept being handled by strangers at shows, they may also be more docile and easily tamed than ordinary pet mice. A fancy mouse that is particularly nervous or hard to handle would not normally be bred from in case these characteristics were passed on to its offspring. This is in contrast to the ordinary pet mouse, which may have been bred for snake food so the breeder has no reason to select for health or temperament.


Fancy mice are extremely pretty. I have yet to see a rat, hamster, or gerbil who can melt hearts like a Siamese Satin mouse (I have one Siamese Satin, Kiki, who is know as Kiki Gorgeous because just about everyone who meets her immediately says, "Oh, isn't she gorgeous?" when they are bowled over by her shiny coat, dark points, big ears, and ruby eyes). They are sleek and polished rather than soft and fluffy. They are very active, playful animals and will entertain you by chasing and grooming each other, playing with their toys, and exploring anything they can get their little noses into. They are very happy animals and it is a joy to see how much pleasure they get from a few simple objects. They are among the more intelligent rodents and can be taught to explore mazes and the like. Although they are naturally shy, mice get to know their owners and can be trained to come to you and climb on your hand. Once a mouse is confident with you, a human becomes a playground with sleeves and pockets to be investigated and fingers to weave through. My mice have taken to mugging me when I put my hand in the cage to pick up the feed bowl-they jump on my hand demanding treats, and then sprint up my sleeve, presumably on the off chance that one day there will be a sunflower seed in my armpit!


A mouse will never be as dog-like as a rat (maybe the size difference is too great for them to relate to us as a companion). Mice will not, for example, be found clinging upside-down to the cage ceiling begging to be let out as soon as they hear you open the door. They are also not likely to play hide-and-seek with you. In fact, tame mice will readily play on you, but will rarely play with you. On the other hand, mice will not take great delight in running riot over your house, peeling wallpaper off the walls, chewing the sofa, throwing things off shelves, stealing food and useless trinkets, or any other of those cute things rats do. This is mainly because mice don't need to be given the run of your house in order to have fun. You can put them in the (empty) bath or on the kitchen table with a few packets and boxes, together with their usual toys arranged in different positions, and they will amuse themselves in a non-destructive way for hours. Generally, mice are much less demanding and less destructive than rats and it is easier to keep them amused. Mice are also cheaper and easier to house than rats. While a two foot aquarium would be a slightly cramped home for a pair of rats, it would make a great pad for a couple of mice. Mice have attractions all of their own, but they are also a good choice of pet for those who would like rats, but do not have the time to give them the attention they need, or the space for a large cage.


Mice, like rats and gerbils, are social animals and should not be kept on their own unless they are so aggressive that they would seriously harm another mouse. (See the section on male mice below for more on this.) They should be kept in at least pairs, and preferably in larger groups. A single mouse will generally be bored and miserable-no amount of human attention can replace the communication, grooming and constant companionship of another member of its own species. Single mice are not good pets-they tend to hide away for most of the day and are far less active than mice kept in groups, possibly because they are depressed. Show mice lose weight and condition rapidly if they are kept alone for more than a day or so, and this can be interpreted as a physical symptom of their unhappiness. Solitary confinement is used as an extreme and cruel punishment for humans and is not deserved by our pets. It takes no more effort to look after two mice than one, and there really is no excuse for keeping a mouse alone unless it has aggression problems.

Unless you want constant litters of baby mice (they can reproduce every three weeks) and exhausted females, it is best to keep mice in single sex groups. Female mice (known as does) can be introduced at any age and will almost invariably live together happily, although there will be some fighting and the odd bitten tail while they establish a hierarchy in the cage if they are introduced as adults. Male mice can usually live together ONLY if introduced when very young and never separated for a long period (more than a day).


Male mice (bucks) can cause problems. They become very aggressive to strange bucks as adults, so must be put together with their future companions as soon as possible after weaning (although litter brothers make the best companions), and at the very latest by six weeks of age (five to be safe) depending on the individual mice involved. Adult bucks introduced to a stranger may well fight to the death; even if fighting does not kill them, stress may. This means that if a buck does not have a companion by the time he is six weeks, or subsequently loses his companion, he will not be able to live with another male.

If he is good enough to breed from, the single buck can be provided with at least three does to live with him in rotation (one with the buck, one nursing young, and one resting after weaning her young). If you do not wish to breed from your single male mouse, you might try to obtain an old female to live with him-after about a year old, does are not likely to have many kittens. However, there are always exceptions and you should be aware that if the doe does conceive, a late pregnancy and lactation could be stressful for her.

One other method of keeping a group of bucks happily together is to put them all, when very young, with an old, preferably infertile doe who will take on a maternal role. The doe seems to have a calming influence on the bucks, and some people have kept up to 25 bucks together in this way. Of course, the bucks may mate with the doe, so you would need to keep a careful eye on her to make sure that she is not being continually pestered.

Bucks living together can still be used for breeding, provided they are not separated. Does can be put into the bucks' cage; they may be mated by all of the males, yet, remarkably, the boys do not seem to fall out in this situation. Some breeders use this method very successfully, but it is probably stressful for the doe and she should not be left with the bucks for longer than is necessary. Once a group of bucks have become established companions, they should not be separated for any length of time and, in particular, if one mouse is taken out of the group to mate with a doe, he will not be accepted by the others on his return. Note that there will usually be some fighting among established groups of males, but this is not usually serious (e.g. loud squeaking over territory rights after the cage has been cleaned). Sometimes even established pairs of bucks fall out and must be separated-if fighting becomes serious (i.e. bleeding wounds as opposed to squeaking and the occasional bitten tail) the most aggressive mouse must be taken out of the group in case a mouse is seriously injured or killed. In particular, watch out for mice which seem depressed-if a buck starts sitting still for long periods without moving and seems to lose his energy and inquisitiveness, it is time to remove either him or the buck who is bullying him from the cage. You should also regularly check that no buck is hiding painful bites under his coat by running your finger against the lie of the hair, so that you can see the skin.

Some types of mice are more aggressive than others. For example, problems may be experienced with the marked varieties such as Spotted and Dutch mice (marked like the Dutch rabbit), and these mice should be watched closely for signs of serious fighting. Much aggressive behavior is hereditary, so careful breeding can help to produce less aggressive mice. While nearly all does live happily in large colonies, some still bully other mice in a continual struggle for dominance. Their sons are likely to inherit a testosterone-enhanced version of this argumentative personality, so it is best to avoid breeding from aggressive does if you want their sons to be able to live together. However, I must stress that many groups of bucks can live together quite happily and, while you should watch out for serious violence, you need not let the odd scrap frighten you into separating them. Their quality of life will be much better if you keep them together. Think of male mice like Australian men-scrapping is a national sport and not to be taken too seriously!

One particularly charming (!) characteristic of male mice is that their urine produces a very strong, extremely pervasive musky smell. This scent marks their territory, so as soon as the cage is cleaned the mice will carefully urinate over everything which they wish to label as their own. If you have them out to play, this could include you and your furniture. Once you have been scent-marked by a male mouse, you will need an immediate shower and change of clothes unless you want to smell like a very strong, cheap musk aftershave all day! If the mice live in the house and the smell becomes a problem, you can more or less eliminate it by plugging in a Remington Air Purifier (£10.75 here, probably KEEPING FANCY MICE CONTINUED FROM PAGE 6 cheaper in the US) near the cage. This will also remove cigarette smoke, pollen, and other pollutants so it is good for humans and mice alike.

It is possible that neutered male mice could live together happily, or at least could live with a group of does for company. Because mice are such small, short-lived animals, it is very rare for surgery to be performed on them outside of laboratories. There is a large risk of them not surviving conventional anesthetic and of them finding the whole experience extremely stressful. So far, I have not met anyone who has tried neutering a male mouse, but my vet is confident that it can be done using isoflurane anesthesia, which is especially suited to small mammals. Since a couple of my bucks are too aggressive to live together, but are thoroughly miserable living alone, I hope to try having one neutered soon and will keep you informed of the results.