House Mouse
The house mouse (Mus musculus) 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 obvious scale rings. They have a small, scaly-tailed mouse with a distinct notch in the cutting surface of upper incisors.
House mice are considered among the most troublesome and economically important rodents in the United States.
Adult house mice weigh about 2/5 to 4/5 ounce (11 to 22 grams). They are generally grayish brown with a gray or buff belly. Similar mice include the white-footed mice and jumping mice (which have a white belly), and harvest mice (which have grooved upper incisor teeth). For more details on species identification, see a field guide such as that by Burt and Grossenheider (1976).
Native to central Asia, this species arrived in North America with settlers from Europe and from other points of origin. A very adaptable species, the house mouse often lives in close association with humans and therefore is termed one of the “commensal” rodents along with Norway and roof rats. House mice are much more common in residences and commercial structures than are rats. Brooks (1973) regards them to be the most common mammal in cities, next to humans.
Habitat
House mice are commonly found in residential, commercial, and agricultural settings, as well as open fields. They may also inhabit areas far from human settlements, especially in moderate climates. In temperate regions, the arrival of cold weather during fall often prompts mice to seek shelter and food within structures.
Food Habits
House mice have diverse diets but favor seeds and grains. They're known as "nibblers," exploring various food items in their surroundings. They may also consume high-fat, high-protein, or sugary foods like bacon, chocolate, butter, and nuts. Unlike other rats, house mice can survive with minimal or no free water, as they obtain moisture from their food. However, access to liquid water or food with sufficient moisture is essential for their breeding potential.
General Biology, Reproduction, and Behavior
House mice are primarily nocturnal but may show daytime activity in certain locations. They rely on hearing, smell, taste, and touch due to poor eyesight. Nests are constructed from shredded materials like paper or burlap and are typically 4 to 6 inches in diameter. They breed year-round, with litters of 5 or 6 born every 19 to 21 days. Mice reach sexual maturity at 6 to 10 weeks and can have 5 to 10 litters per year.
Mice are adept at gaining entry to structures through gnawing, climbing, jumping, and swimming. They have a limited range of about 10 to 30 feet for food and water. Mice quickly adapt to new objects but may reject baits based on taste. Bait shyness can occur if bait causes illness, but prebaiting can prevent this. Chronic baits typically do not cause bait shyness.
Damage and Damage Identification
House mice, when present in or around structures, often cause economic damage by feeding on stored food items, contaminating food with urine, droppings, and hair, and damaging packaging materials in warehouses. They may also cause structural damage through gnawing and nest-building activities, posing fire hazards by chewing on wiring in appliances. Additionally, they can damage stored items such as family heirlooms and transmit diseases such as salmonellosis, rickettsialpox, and lymphocytic choriomeningitis, among others, to humans and animals.
Mouse Signs
The presence of house mice can be determined by a number of signs described below:
Mouse droppings, typically about 1/4 inch (0.6 cm) long, are found along runways, feeding areas, and near shelter. Differentiating between mouse droppings and those of insects like cockroaches can be challenging; cockroach droppings are usually 1/8 to 1/4 inch (0.3 to 0.6 cm) long with distinct longitudinal ridges and squared-off ends. Tracks, including footprints and tail marks, may be visible on dusty surfaces or in mud. A tracking patch made of flour can reveal rodent presence overnight. Urine, wet or dry, fluoresces under ultraviolet light. Rub marks, stains, and odors along travelways or in feeding areas also indicate mouse activity. Gnawing sounds and musky odors are common signs. While these signs provide clues, tracking-dust patches left out for over 24 hours can help estimate the size of the mouse population more accurately.
Damage Prevention and Control Methods
Exclusion
Seal all openings larger than 1/4 inch (0.6 cm) wide.
Habitat Modification
Good sanitation practices reduce sources of food, water, and shelter. Store foodstuffs in rodent-proof structures or containers. Control weeds and remove debris from around structures.
Cowleys Pest Services is your local expert for pest control, including prevention of rodents such as house mice and rats. Our services are available in Edison, Lakewood, Somerset, Toms River, Brick, Bridgewater, Piscataway, Old Bridge, Middletown, Princeton Junction and surrounding New Jersey. For a free consultation, contact us today!
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