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Mus musculushouse mouse

By Liz Ballenger

Geographic Range

Mus musculus may have originally been distributed from the Mediterranean region to China, but it has now been spread throughout the world by humans and lives as a human commensal.

Habitat

House mice generally live in close association with humans-- in houses, barns, granaries, etc. They also occupy cultivated fields, fencerows, and even wooded areas, but they seldom stray far from buildings. Some individuals spend the summer in fields and move into barns and houses with the onset of cool autumn weather. Because of their association with humans, house mice have been able inhabit inhospitable areas (such as tundra and desert) which they would not be able to occupy independently.

Physical Description

House mice are from 65 to 95 mm long from the tip of their nose to the end of their body, their tails are 60 to 105 mm long. Their fur ranges in color from light brown to black, and they generally have white or buffy bellys. They have long tails that have very little fur and have circular rows of scales (annulations). House mice tend to have longer tails and darker fur when living closely with humans. They range from 12 to 30 g in weight. Many domestic forms of mice have been developed that vary in color from white to black and with spots.

  • Sexual Dimorphism
  • sexes alike
  • Range mass
    12.0 to 30.0 g
    0.42 to 1.06 oz
  • Range length
    65.0 to 95.0 mm
    2.56 to 3.74 in
  • Average basal metabolic rate
    0.271 W
    AnAge

Reproduction

House mice have a polygynous mating system. The recent discovery of ultrasonic songs produced by male mice, when exposed to female sex pheromones, suggests that this behavior may be involved in mate choice. (Holy and Guo, 2005)

Mus musculus is characterized by tremendous reproductive potential. Breeding occurs throughout the year, although wild mice may have a reproductive season extending only from April to September. The estrous cycle is 4-6 days long, with estrus lasting less than a day. Females experience a postpartum estrus 12-18 hours after giving birth. Females generally have 5-10 litters per year if conditions are suitable, but as many as 14 have been reported. Gestation is 19-21 days but may be extended by several days if the female is lactating. Litters consist of 3-12 (generally 5 or 6) offspring, which are born naked and blind. They are fully furred after 10 days, open their eyes at 14 days, are weaned at 3 weeks, and reach sexual maturity at 5-7 weeks. Average life span is about 2 years in captivity, but individuals have lived for as long as 6 years. In the wild, most mice do not live beyond 12-18 months.

  • Breeding season
    Throughout the year
  • Range number of offspring
    3.0 to 12.0
  • Average number of offspring
    5.0
  • Average number of offspring
    7
    AnAge
  • Range gestation period
    21.0 (high) days
  • Average weaning age
    21.0 days
  • Range age at sexual or reproductive maturity (female)
    5.0 to 7.0 weeks
  • Range age at sexual or reproductive maturity (male)
    5.0 to 7.0 weeks

Young mice are cared for in their mother's nest until they reach 21 days old. Soon after this most young mice leave their mother's territory, though young females are more likely to stay nearby.

  • Parental Investment
  • altricial
  • pre-fertilization
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • female

Lifespan/Longevity

If a house mouse is a pet, the average life span is about 2 years, but mutant and calorie-restricted captive individuals have lived for as long as 5 years. Wild-derived captive Mus musculus individuals have lived up to 4 years in captivity. In the wild, most mice do not live beyond 12-18 months.

  • Range lifespan
    Status: wild
    12.0 to 18.0 months
  • Range lifespan
    Status: captivity
    5.0 (high) years
  • Average lifespan
    Status: captivity
    2.0 years
  • Typical lifespan
    Status: wild
    12.0 to 18.0 months
  • Typical lifespan
    Status: captivity
    5 (high) years
  • Average lifespan
    Status: captivity
    2.0 years

Behavior

In the wild state, house mice generally dwell in cracks in rocks or walls or make underground burrows consisting of a complex network of tunnels, several chambers for nesting and storage, and three or four exits. When living with humans, house mice nest behind rafters, in woodpiles, storage areas, or any hidden spot near a source of food. They construct nests from rags, paper, or other soft substances and line them with finer shredded material. House mice are generally nocturnal, although some are active during the day in human dwellings. House mice are quick runners (up to 8 miles per hour), good climbers, jumpers, and also swim well. Despite this, they rarely travel more than 50 feet from their established homes.

Mus musculus is generally considered both territorial and colonial when living commensally with humans. Territoriality is not as pronounced in wild conditions, however. Dominant males set up a territory including a family group of several females and their young. Occasionally, subordinate males may occupy a territory or males may share territories. Females establish a loose hierarchy within the territories, but they are far less aggressive than males. Aggression within family groups is rare, but all the individuals in a territory will defend an area against outsiders. Young mice are generally made to disperse through adult aggression, although some (especially females) may remain in the vicinity of their parents.

Communication and Perception

House mice have excellent vision and hearing, a keen sense of smell, and use their whiskers to feel air movements and surface textures. House mice often squeak to each other in the nest. They use pheromones and other smells to communicate with each other about social dominance, family composition, and reproductive readiness. It was recently discovered that male mice produce complex, ultrasonic songs in response to female sex pheromones. (Holy and Guo, 2005)

Food Habits

In the wild, house mice eat many kinds of plant matter, such as seeds, fleshy roots, leaves and stems. Insects (beetle larvae, caterpillars, and cockroaches) and meat (carrion) may be taken when available. In human habitation, Mus musculus consumes any human food that is accessible as well as glue, soap, and other household materials. Many mice store their food or live within a human food storage facility.

  • Animal Foods
  • carrion
  • insects
  • terrestrial non-insect arthropods
  • Plant Foods
  • leaves
  • roots and tubers
  • wood, bark, or stems
  • seeds, grains, and nuts
  • fruit

Predation

House mice are eaten by a wide variety of small predators throughout the world, including cats, foxes, weasels, ferrets, mongooses, large lizards, snakes, hawks, falcons, and owls. House mice try to avoid predation by keeping out of the open and by being fast. They are also capable of reproducing very rapidly, which means that populations can recover quickly from predation.

Ecosystem Roles

Where house mice are abundant they can consume huge quantities of grains, making these foods unavailable to other (perhaps native) animals. House mice are also important prey items for many small predators.

Species Used as Host
  • Humans

Economic Importance for Humans: Positive

Domesticated forms and albinos have been developed which are commonly used as laboratory animals (especially in medicine and genetics), and as pets. Mus musculus also has a small role as an insect destroyer, but this is minimal.

  • Positive Impacts
  • pet trade
  • research and education
  • controls pest population

Economic Importance for Humans: Negative

House mice do not cause such serious health and economic problems as do Rattus norvegicus and Rattus rattus. Mice are agricultural pests in some areas, however, and they do consume and contaminate stored human food with their droppings. They also destroy woodwork, furniture, upholstery, and clothing. In addition, they contribute to the spread of diseases such as murine typhus, rickettsial pox, tularemia, food poisoning (Salmonella), and bubonic plague. Recent research has also shown that they carry a virus--the mouse mammary tumor virus (MMTV)--that may contribute to breast cancer in humans. (Indik, et al., 2005; Stewart, et al., 2000)

  • Negative Impacts
  • injures humans
    • carries human disease
  • crop pest
  • household pest

Conservation Status

Commensal populations of Mus musculus are generally stable and densities can be as high as 10 mice per square meter. In the wild, populations are less stable and densities may be less than 1 mouse per 100 square meters. Overall, populations are flourishing and are in fact aided by human construction of houses, barns, and other structures.

Other Comments

Mus musculus often refers to several fairly distinct kinds of mice. As many as seven separate species may be placed under Mus musculus, such as Mus domesticus, western European house mice, and Mus castaneus, southeastern Asian house mice. "Dancing" and "singing" mice are other names for house mice. The former refers to a genetic strain with inner ear defects, causing the mice to weave, turn in circles, and wobble when they walk. The latter refers to a pathological condition causing mice to twitter constantly with a "song" resembling that of a cricket. (Sage, et al., 1993)

Contributors

Allison Poor (editor), University of Michigan-Ann Arbor.

Liz Ballenger (author), University of Michigan-Ann Arbor.

Glossary

Australian

Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.

World Map

Ethiopian

living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.

World Map

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

Neotropical

living in the southern part of the New World. In other words, Central and South America.

World Map

Palearctic

living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.

World Map

acoustic

uses sound to communicate

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carrion

flesh of dead animals.

chemical

uses smells or other chemicals to communicate

cosmopolitan

having a worldwide distribution. Found on all continents (except maybe Antarctica) and in all biogeographic provinces; or in all the major oceans (Atlantic, Indian, and Pacific.

dominance hierarchies

ranking system or pecking order among members of a long-term social group, where dominance status affects access to resources or mates

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

fertilization

union of egg and spermatozoan

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

internal fertilization

fertilization takes place within the female's body

introduced

referring to animal species that have been transported to and established populations in regions outside of their natural range, usually through human action.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

oceanic islands

islands that are not part of continental shelf areas, they are not, and have never been, connected to a continental land mass, most typically these are volcanic islands.

omnivore

an animal that mainly eats all kinds of things, including plants and animals

oriental

found in the oriental region of the world. In other words, India and southeast Asia.

World Map

pet trade

the business of buying and selling animals for people to keep in their homes as pets.

pheromones

chemicals released into air or water that are detected by and responded to by other animals of the same species

polygynous

having more than one female as a mate at one time

scrub forest

scrub forests develop in areas that experience dry seasons.

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

social

associates with others of its species; forms social groups.

stores or caches food

places a food item in a special place to be eaten later. Also called "hoarding"

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

ultrasound

uses sound above the range of human hearing for either navigation or communication or both

visual

uses sight to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

year-round breeding

breeding takes place throughout the year

References

Jackson, H.H.T. 1961. Mammals of Wisconsin. The University of Wisconsin Press, Madison, Wisconsin.

Kurta, A. 1995. Mammals of the Great Lakes Region. The University of Michigan Press, Ann Arbor, Michigan.

Nowak, R.M. and J.L Paradiso. 1983. Walker's Mammals of the World. 4th edition. John Hopkins University Press, Baltimore, Maryland.

Holy, T., Z. Guo. 2005. Ultrasonic songs of male mice. Public Library of Science, Biology, 3/12. Accessed November 02, 2005 at http://biology.plosjournals.org/perlserv/?request=get-document&doi=10.1371/journal.pbio.0030386.

Indik, S., W. Günzburg, B. Salmons, F. Rouault. 2005. Mouse mammary tumor virus infects human cells. Cancer Research, 65 (15): 6651-6659.

Sage, R., W. Atchley, E. Capanna. 1993. House mice as models in systematic biology. Systematic Biology, 42(4): 523-561.

Stewart, T., R. Sage, A. Stewart, D. Cameron. 2000. Breast cancer incidence highest in the range of one species of house mouse, Mus domesticus. British Journal of Cancer, 82(2): 446-451.

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