The house mouse is a small, slender rodent that has a slightly pointed nose; small, black, somewhat protruding eyes; large, sparsely haired ears; and a nearly hairless tail with scale rings. House mice are considered among the most troublesome and economically damaging rodents in Britain. Adult house mice weigh from 1/2 to 1 ounce. They are generally greyish brown with a grey or buff belly.
The house mouse is very adaptable and often lives in close association with humans. Therefore it is known as a "commensal" rodent as are brown rats. House mice are much more common in residences and commercial structures than are rats. Next to humans, it is regarded to be the most common mammal in cities.
Where do they live?
House mice live in and around homes, farms, commercial establishments, and in open fields and agricultural lands. At times they may be found living far from human settlements, particularly where climates are moderate. House mice eat many types of food but prefer seeds and grain. They are not hesitant to eat new foods and are considered "nibblers," sampling many kinds of items that may exist in their environment. Foods high in fat, protein, or sugar may be preferred even when grain and seed are present. Such items include bacon, sweets, and butter. Unlike brown rats, house mice can survive with little or no free water obtaining their water from the food they eat.
House mice are mainly nocturnal, although in some areas a lot of daytime activity may be seen. Seeing mice during the day does not necessarily mean that a high population is present, although this is usually true for rats. They may nest in the ground or in any protected location. Nests are constructed of shredded fibrous materials such as paper, or other similar items, and generally have the appearance of a "ball" of material loosely woven together. Nests are usually 4 to 6 inches in diameter. Litters of 5 or 6 young are born 19 to 21 days after mating, although females that conceive while still nursing may have a slightly longer gestation period. Mice are born hairless and with their eyes closed. They grow rapidly, and after 2 weeks their eyes and ears open and they are covered with hair. They begin to make short excursions from the nest and eat solid food at 3 weeks. Weaning soon follows, and mice are sexually mature at 6 to 10 weeks of age.
Why are there so many?
Mice may breed year-round. The female has 5 to 10 litters per year. Mouse populations can therefore grow rapidly under good conditions. Studies indicate that during its daily activities, a mouse normally travels an area averaging 10 to 30 feet in diameter. Mice seldom travel farther than this to obtain food or water. Because of their limited movement and feeding behaviour they are much more difficult to control in some situations.
Do they do any harm?
When house mice live in or around structures, they almost always cause some degree of economic damage. In homes and commercial buildings, they may feed on various stored food items or pet foods. In addition, they usually contaminate foodstuffs with their urine, droppings, and hair. A single mouse eats only about 8 pounds of food per year but destroys considerably more food than it consumes because of its habit of nibbling on many foods and discarding partially eaten items. Pest Control of Mice House mice cause damage to buildings by their gnawing and nest-building activities. House mice often make homes in large electrical appliances, and here they may chew up wiring as well as insulation, resulting in short circuits which create fire hazards or expensive damage. Mice may also damage stored items in attics, basements, garages, or museums. Damaged family heirlooms, paintings, books, documents, and other such items may be impossible to replace.
Among the diseases mice or their parasites may transmit to humans are salmonellosis (food poisoning), rickett-sialpox, and lymphocytic choriomeningitis. Mice may also carry leptospirosis, rat bite fever and tapeworms.