House mouse (Mus musculus)

French: Souris Domestique
Spanish: Ratón Casero
GenusMus (1)
SizeHead-body length: 6 - 10 cm (2)
Weight12 - 22 g (2)

The house mouse is classified as Least Concern (LC) on the IUCN Red List (7).

The house mouse (Mus musculus) 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).

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).

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).

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).

Not relevant.

Not relevant.

For more on British mammals see the Wild About Britain website:

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:

  1. National Biodiversity Network Species Dictionary (September 2003):
  2. Mammals Trust UK (September 2003):
  3. Corbet, G. B. & Southern, H. N. (1977) The handbook of British mammals. Second Edition. Blackwell Scientific Publications, London.
  4. Animal Diversity Web (September 2003):
  5. Macdonald, D (2001) The new encyclopaedia of mammals. Oxford University Press, Oxford.
  6. Buczaki, S (2002) Fauna Britannica. Hamlyn, London.
  7. IUCN Red List (February, 2011)