A fancy mouse (fancy means 'hobby' in this context) is a domesticated form of the house mouse (Mus musculus ), one of many mouse species, usually kept as a type of pocket pet. Fancy mice have also been specially bred for exhibiting, with shows being held internationally. A pet mouse is inexpensive compared to larger pets, and even many other pet rodents, but mice are comparatively short-lived: typically only 2 to 3 years.
The term fancy mouse is used to describe a mouse that has been selectively bred for exhibition. Wild-caught specimens that become docile and are bred for many generations still fall under the fancy type. Fancy mice can vary greatly in size, from small pet mice that are approximately 5–8 cm (2–3 in) long from nose to the proximal start of the tail, to show mice that measure 8 cm (3.1 in) nose to tail. Pet mice weigh about 29–44 g (1.0–1.6 oz) but large show mice can weigh up to 130 g (4.6 oz).
Food for fancy mice can range from specially formulated feed mix to kitchen scraps. Carrot, spinach, lettuce and other vegetables are often enjoyed by mice but should be given sparingly as such foods can result in diarrhoea and life-threatening dehydration. Bread crumbs, wheat and rice can also be good for mice. Laboratories keeping mice as experimental subjects almost uniformly use a product called lab block, a scientifically formulated blend originally designed for mice in laboratories. In order to keep variety in their diets, mice can also eat oats, oily seeds, clean eggshell, breakfast cereal, and stale bread. Fruit and vegetables are part of a more natural and healthful diet. Some owners give it to them as a treat after they do a trick. Mice often chew wood and other hard substances, which keeps their teeth from growing too long. As mice and rats have similar diets, some pet mouse owners choose to feed them rat food. Although it is common practice to feed premixed diets designed for other rodents, for the longevity and health of the animal it is best to feed mouse-targeted diets. Diets for hamsters, for instance, are known to contain higher protein than what is required for mice or rats.Show More
House mice primarily feed on plant matter, but they will also accept meat and dairy products. Meats are full of protein and are good for pregnant or nursing mice. They will drink water, but require little of it, relying mainly on the moisture present in their food. If a water source is provided, then a gravity bottle feeder is necessary for maintaining the cleanliness of the water supply. They will eat their feces to acquire nutrients produced by bacteria in their intestines, a behavior they share with rabbits and guinea pigs called coprophagy. House mice, like other rodents, do not vomit.Show Less
Mice have a rapid reproduction rate; the gestation period is approximately 19 to 23 days. The average litter size is four to 12 young. In some instances, up to 30 young have been born. However females have 10 nipples so may only feed this many pups at any one time. The pups in larger litters are often weaker, smaller animals that can weaken the doe, increasing recovery time. Litters can be humanely culled to 10-12 mice at the very most. Males can mate with the female as soon as the litter is born, which means that a female could become pregnant with another litter within three days of giving birth. Female mice should not be bred before 12 weeks or after eight months; doing so can be very dangerous, and some mice can die while giving birth. Females come into heat around every three to five days, so the pair can be kept together for up to 10 days.Baby mice, called pinkies or pups, are born blind, deaf, and naked. Their eyes are closed and their ears are stuck to the sides of their heads. Mothers may eat any dead or sickly offspring. Pups begin to grow hair at 2 to 4 days. Ears open at 3 to 5 days, and the pups will start vocalising. Eyes open at 14 days, and the pups will start exploring the world around them. At 3 weeks old, they look like miniature versions of adult mice. At 4 weeks the males in the litter should be removed, lest they impregnate their mother and sisters, while the females can be left with the mother.
The first written reference to mice kept as pets occurs in the Erya, the oldest extant Chinese dictionary, from a mention in an 1100 B.C. version. In Europe the breeding of fancy mice became popular through the introduction of Japanese stock in the early 17th century. By 1895, Walter Maxey founded the National Mouse Club in Victorian England, with its first official show held in Lincoln that year. Since that time, mouse clubs have formed worldwide. Shows are held so competitive breeders can display their mice, where they are judged on colour, body shape and behaviour.Show More
Mice are kept as pets in many countries for a number of reasons: Fancy mice are relatively small, inexpensive, never need bathing, and can learn to enjoy regular handling if provided with the correct care. Female mice are popular with many owners, since they tend to co-habitate with other mice better than males. Additionally, the urine of female fancy mice does not contain as strong an odor as that of male mice. Bucks will often fight with and kill each other when housed together, despite being raised together, due to their very strong and unchangeable territorial instincts. It is difficult to house male mice together without the risk of injury to one or both males. Some people, however, prefer the personality and curiosity of male mice. It is a good idea to keep fancy mice in groups of at least two if possible, as mice are sociable animals. However, if a buck and a doe of breeding age are put in the same cage, it is possible for them to reproduce at a maximum frequency of once every three weeks. Litters of five to 18 are not unusual.Show Less