A mouse (plural mice) is a small mammal belonging to the order of rodents. The best known mouse species is the common house mouse (Mus musculus). It is also a popular pet. The American white-footed mouse (Peromyscus leucopus) and the deer mouse (Peromyscus maniculatus) also sometimes live in houses.

Although mice may live up to two and a half years in captivity, the average mouse in the wild lives only about four months,Fact: date=December 2008 primarily owing to heavy predation. Cats, wild dogs, foxes, birds of prey, snakes and even certain kinds of insects have been known to prey heavily upon mice. Nevertheless, because of its remarkable adaptability to almost any environment, and its ability to live commensally with humans, the mouse is regarded to be the second most successful mammalian genus living on Earth today, after humans.

Mice can at times be harmful pests, damaging and eating crops and spreading diseases through their parasites and feces. In western North America, breathing dust that has come in contact with mouse feces has been linked to the deadly hantavirus.Fact: date=December 2008. The original motivation for the domestication of cats is thought to have been for their predation of mice and their relatives, the rats.Fact: date=December 2008

Distribution and habitat

All species of Mus are native to Eurasia and Africa, where they range from lowlands to mountaintops. The five species in the subgenus Pyromys are found in Sri Lanka, India, Pakistan, and mainland Southeast Asia. Much of their range originally consisted of open grasslands or grassy patches in forests.

Reproduction

Female mice housed together tend to go into anestrus and do not cycle. If exposed to a male mouse or the pheromones of a male mouse, most of the females will go into estrus in about 72 hours. This synchronization of the estrous cycle is known as the Whitten effect. The exposure of a recently bred mouse to the pheromones of a strange male mouse may prevent implantation (or pseudopregnancy), a phenomenon known as the Bruce effect.

The average gestation period is 20 days. A fertile postpartum estrus occurs 14-24 hours following parturition, and simultaneous lactation and gestation prolongs gestation 3-10 days owing to delayed implantation. The average litter size is 10-12 during optimum production, but is highly strain dependent. As a general rule, inbred mice tend to have longer gestation periods and smaller litters than outbred and hybrid mice. The young are called pups and weigh at birth, are hairless, and have closed eyelids and ears. Cannibalism is uncommon, but females should not be disturbed during parturition and for at least 2 days postpartum. Pups are weaned at 3 weeks of age; weaning weight is . If the postpartum estrus is not utilized, the female resumes cycling 2-5 days postweaning.