The house mouse is a delicate, agile, little rodent. It has a slightly pointed nose; relatively small feet; small, black, somewhat protruding eyes; large, sparsely-haired ears; and a nearly hairless tail about as long as its body, with obvious scale rings. They vary in colour but are generally grayish-brown throughout with a gray or buff belly.
Adults weigh 10-30 g (2/5 to one oz.) and measure 65 to 90 mm (2 1/2 to 3 3/4 in.) in total body length, including the tail.
The house mouse is not native to North America. It originated from Asia, arriving and travelling across North America with settlers from Europe and elsewhere.
A very adaptive species, the house mouse depends upon man for shelter and food, particularly in cooler climates, and this close association with humans classifies it as a “commensal rodent” (like the Norway rat).
Mice are mainly nocturnal; however, house mice and meadow voles may be active during the day at some locations. Seeing mice during daylight hours does not necessarily mean that a high population is present, although this is usually true for rats.
Mice usually bear a litter of five to six young, following a 21 to 23-day gestation period. White-footed mice may have more than one litter per year, and house mice living indoors can have up to 10 litters per year.
Young mice are weaned at about 21days, and females can mate at about 35 to 49 days. Lifespan is usually short, ranging from four to 20 months. Mice do not hibernate, but white-footed mice may become completely inactive for a few days when winter weather is severe.
The nest of a mouse is usually ball-shaped and consists of shredded fibrous material such as paper, burlap, and stems, leaves, twigs, etc. It may be lined with hairs, feathers and shredded cloth.
The meadow vole commonly constructs underground tunnels and surface runways with numerous entrances. Similarly, house mice construct runways under flat surfaces such as plywood, sheeting or boards.
White-footed mice spend a great deal of time in trees. Occasionally they re-furbish abandoned bird or squirrel nests, by adding a protective “roof” of twigs and leaves. Generally, all mice nest at, or below ground level, or in buildings.
Mice possess amazing physical capabilities that enable them to gain entry to structures by climbing, crawling, jumping or gnawing. Mice are also good swimmers, particularly meadow voles which are known to cross open water to seek food and shelter.
However, the house mouse out-performs all mice in physical capabilities which makes control of it more difficult. Also, house mice constantly explore their environment and can be found in a wider range of locations.
Most mice quickly detect new objects in their environment but, unlike rats, do not fear them. Therefore, they will almost immediately enter bait stations and traps or cross glueboards, and willingly sample new food items.
Studies indicate that mice normally travel within an area averaging 3 to 10 m (10 to 30 ft.) in diameter to obtain food, shelter and water.
Damage Caused by Mice
Mice cause a wide variety of problems ranging from chewing upholstered furniture to girdling trees in orchards. Economic damage caused by mice can be categorized into three areas: food and feed consumption, structural damage to buildings, and, other damage related to their habits of chewing and digging.
Voles often girdle shelterbelt seedlings and native trees. Voles also eat crops and damage them when they build extensive runways and tunnel systems. All mice have a very keen sense of smell and can locate and dig up seeds buried 15 cm (6 in.) deep.
In addition to their destructive habits, mice, and particularly house and white-footed mice, are implicated in the transmission of several disease organisms. In 1993, the white-footed mouse was identified as a potential reservoir of a type of hantavirus responsible for an adult respiratory distress syndrome in western Canada.