Mus musculus

The house mouse is one of the most widely distributed and successful mammals in the world (2). It has dull greyish-brown fur and the tail, which is the same length as the body, is thicker and scalier than that of other species of mice (3). It is accompanied by a distinctive strong 'stale' odour and its presence can easily be detected by means of its droppings (2). Forms of this species living in association with man ('commensal' forms) tend to be larger and darker than 'wild' forms, and have longer tails (3). The voice is a familiar high-pitched 'squeak' (3).

House mice are typically active at night, but will emerge during the day if food is scarce (3). They are extremely agile, with an excellent sense of balance, and are able to jump and swim fairly well (3). The senses of hearing and smell are highly developed and communication is largely through scent (5). They have an extremely broad diet, incorporating most human foodstuffs, invertebrates and occasionally more bizarre household items such as soap and tobacco (2). In urban situations, territories are usually set up, which males defend aggressively (3). Breeding tends to occur throughout the year, with five to ten litters produced each year, each one consisting of between four and eight young (3). The nest is constructed of shredded matter such as paper or cloth (2) and females may share a nest if the population density is high (3) . The young are born virtually hairless, with sealed eyes and ears. They are fully furred after 14 days and weaned after 18 - 20 days, when they begin to emerge from the nest (3).  House mice are well-known pests, contaminating foodstuffs and grains and carrying a number of diseases and parasites that are transmissible to humans (3). Its close association with humans has led to it featuring widely in folklore (6).

Mice can jump a vertical distance of over 12 inches.

Common rodent originating from the Asian continent that often considered a pest organism and is popular as a mammallian model in biomedical studies.

Globally, see GBIF.

Linnæus, C. 1758. Systema naturæ

Mus musculus was originally a Palaearctic species, but through its close association with humans it has been widely introduced across the globe (Musser and Carleton, 2005). The species is widespread over all continents, except Antarctica, and has become established in North and South America, sub-Saharan Africa, Australia, and many oceanic islands (Macholán 1999). The list of countries of occurrence is incomplete.

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.

Biogeographic Regions: nearctic (Introduced ); palearctic (Native ); oriental (Introduced ); ethiopian (Introduced ); neotropical (Introduced ); australian (Introduced ); oceanic islands (Introduced )

Other Geographic Terms: cosmopolitan

occurs (regularly, as a native taxon) in multiple nations

Canada

Origin: Exotic

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

United States

Origin: Exotic

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: Native to Old World. Spread over the world's continents and islands (except Antarctica) in association with humans (Musser and carleton, in Wilson and Reeder 2005).

It is thought that the house mouse originated on the steppes of central Asia and possibly the Mediterranean area. It is now found around the world as a result of introduction by humans. It is known that the species has been present in Britain since at least the Iron Age, as remains have been found in deposits dating from this period. At present, the species is found throughout Britain and Ireland where there are human settlements (3).

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.

Range mass: 12.0 to 30.0 g.

Range length: 65.0 to 95.0 mm.

Other Physical Features: endothermic ; homoiothermic; bilateral symmetry

Sexual Dimorphism: sexes alike

Average basal metabolic rate: 0.271 W.

Length: 20 cm

Weight: 23 grams

Habitat and Ecology

Systems

• Terrestrial

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.

Habitat Regions: temperate ; terrestrial

Terrestrial Biomes: forest ; scrub forest

Comments: Occupies buildings/other structures, as well as natural habitats such as fields, cropland, and (in Hawaii) low elevation forests, beaches, sometimes high elevation forest and scrub (Tomich 1986, Sugihara 1997). In some areas, movement into buildings coincides with the onset of cold weather in late fall. Young are born in a nest that may be communally constructed in a well-concealed site.

As a commensal species, the house mouse lives in close association with humans (4). In addition to houses, it has been found in a range of urban situations, including shops, mills, warehouses, factories, coal mines and even cold stores. In rural areas it occurs in farm buildings, rubbish tips, piggeries, poultry houses, granaries and open fields (3). They nest in woodpiles, beneath floors, behind rafters and in other concealed locations. In the wild state, the house mouse lives in crevices in rocks or in underground burrows (4).

Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.

Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

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

Foraging Behavior: stores or caches food

Primary Diet: omnivore

Comments: Variable diet of plant/animal foods.

In Great Britain and/or Ireland:
Animal / parasite / endoparasite
tapeworm of Hymenolepis nana endoparasitises intestine of Mus musculus (albino)

Animal / parasite / ectoparasite / blood sucker
Nosopsyllus fasciatus sucks the blood of body of Mus musculus (albino)
Other: major host/prey

Animal / parasite / ectoparasite
Polyplax serrata ectoparasitises body of Mus musculus (albino)

Animal / parasite / endoparasite
Syphacia endoparasitises caecum of Mus musculus (albino)
Other: major host/prey

Animal / parasite / endoparasite
Eimeria falciformis endoparasitises Mus musculus
Other: sole host/prey

In Great Britain and/or Ireland:
Animal / parasite / endoparasite
tapeworm of Hymenolepis nana endoparasitises intestine of Mus musculus

Animal / parasite / ectoparasite / blood sucker
Nosopsyllus fasciatus sucks the blood of body of Mus musculus
Other: major host/prey

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

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.

Known Predators:

• domestic cats (Felis silvestris)
• red foxes (Vulpes vulpes)
• weasels (Mustela)
• ferrets (Mustela)
• mongooses (Herpestidae)
• large lizards (Squamata)
• snakes (Serpentes)
• hawks (Accipitridae)
• falcons (Falconidae)
• owls (Strigiformes)

Mus musculus is prey of:
Athene cunicularia
Squamata
Strigiformes
Accipitridae
Falconidae
Herpestidae
Mustela
Felis silvestris
Vulpes vulpes

Based on studies in:
USA: California, Cabrillo Point (Grassland)

This list may not be complete but is based on published studies.

Lives in colonies. Densities vary greatly. Peak densities reach 750 or more individuals per ha (Lidicker 1966). Peaks in abundance (irruptions) occur late summer-fall in Hawaii (Tomich 1986). Home range is less than an acre.

On western Mauna Kea, Hawaii, Amarasekare (1994) found no evidence that this species preys on eggs, young, or adults of endemic birds.

As commensal animals, house mice live in close association with man — in his houses, outbuildings, stores, and other structures. Where conditions permit, feral mice may be found in fields, along watercourses, and in other places where vegetation is dense enough to afford concealment. These feral animals make runways through the grass, or they may utilize runways made by cotton rats and other meadow-inhabiting species. In the agricultural regions where irrigation is practiced house mice often are found in the vegetation along irrigation ditches, sometimes sharing common runways with native mice (Mammals of Texas-House mouse).

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.

Communication Channels: acoustic ; chemical

Other Communication Modes: pheromones

Perception Channels: visual ; acoustic ; ultrasound

Comments: Primarily nocturnal, though also diurnal during population peaks.

Maximum longevity: 4 years (captivity) Observations: A major model of biomedical research, mice are amongst the fastest ageing mammals exhibiting a variety of physiological, functional and pathological changes with age. The record longevity for normal mice is 4 years, belonging to one wild-derived specimen (Miller et al. 2002). Mutant and caloric restricted mice, however, can live over 4 years (Bartke and Brown-Borg 2004), though these are not deemed suitable for species comparisons. Record longevity belongs to a mutant dwarf mouse that lived 1819 days (Andrzej Bartke, pers. comm.). Smaller mice tend to live longer (Miller et al. 2002).

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.

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.

Mating System: polygynous

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.

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.

Key Reproductive Features: iteroparous ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (Internal ); viviparous

Average birth mass: 1.25 g.

Average number of offspring: 7.

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)

Breeds throughout the year under mild indoor conditions, breeds seasonally in natural habitats. Gestation lasts 19-21 days (may be longer if female is lactating). Young are weaned in about 18 days. Produces many litters of 3-12 (typically 4-5) young per year. Sexually mature in 5-10 weeks.

Female house mice have an estrous cycle that is 4-6 days long, with estrus itself lasting less than a day. If several females are held together under crowded conditions, they will often not have an estrus at all; if they are then exposed to male urine, they will become estrous after 72 hours. The gestation period is about 19-21 days, and they give birth to a litter of 3-14 young (average 6-8). One female can have some 5-10 litters per year, so their population can increase very quickly. Breeding occurs throughout the year (however, animals living in the wild don't reproduce in the colder months, even though they don't hibernate). The newborn are blind and furless. Fur starts to grow some three days after birth and the eyes open one to two weeks after birth. Females reach sexual maturity at about 6 weeks and males at about 8 weeks, but both can breed as early as five weeks. House mice usually live under a year in the wild, because of a high level of predation and exposure to harsh environments. In protected environments, however, they often live two to three years. The Methuselah Mouse Prize is a competition to breed or engineer extremely long-lived laboratory mice. As of 2005, the record holder was a genetically engineered mouse that lived for 1819 days, nearly 5 years. Another record holder that was kept in a stimulating environment but did not receive any genetic, pharmacological or dietary treatment lived for 1551 days, over 4 years.

21 chromosomes

Mouse Genome Sequencing Consortium

Year Assessed

Assessor/s

Reviewer/s

Justification

History

• 1996
  Lower Risk/least concern

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.

US Federal List: no special status

CITES: no special status

State of Michigan List: no special status

IUCN Red List of Threatened Species: least concern

Non-native, resident.

Canada

Rounded National Status Rank: NNA - Not Applicable

United States

Rounded National Status Rank: NNA - Not Applicable

Rounded Global Status Rank: G5 - Secure

Very common (3).

Population

Population Trend

Major Threats

Not relevant.

Conservation Actions

Management Requirements: See Olson and Lewis (1995) for information on damage prevention and control techniques, including exclusion, proper sanitation, and lethal and nonlethal control methods (e.g., repellents, toxicants, traps).

Not relevant.

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.

Negative Impacts: injures humans (carries human disease); crop pest; household pest

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

Comments: Often a pest when associated with humans. Consumes stored foods; contaminates about ten times as much food as it consumes. Nest construction and chewing may damage appliances and wiring, sometimes resulting in fires. Involved in the transmission of several diseases, including hantavirus, which causes often-fatal respiratory distress syndrome in humans. See Olson and Lewis (1995).

Mice are genetically very similar to humans. They also reproduce rapidly, have short life spans, are inexpensive and easy to handle, and can be genetically manipulated at the molecular level.

In addition to the human genome, the genomes of about 800 organisms have been sequenced in recent years. These include the mouse Mus musculus, the fruitfly Drosophila melanogaster, the worm Caenorhabditis elegans, the bacterium Escherichia coli, the yeast Saccharomyces cerevisiae, the plant Arabidopsis thaliana, and many microbes.

Genome sizes of Mus musculus being studied

organism: Mus musculus (mouse)

estimated size (base pairs): 2.6 billion

estimated gene number: ~25,000

average gene density: 1 gene per 100,000 bases

chromosome number: 40