House Mouse

Scientific Name: Mus Musculus or Mus Domesticus
Taxonomy: Order Rodentia, Family Muridae

Description: 

House mice are the smallest of the common rodents. They can be distinguished from juvenile rats by their smaller head and feet, and more slender, bi-colored tail. Adult mice weigh between 13 to 28 g (0.5-1 oz.) and have an overall length of 150 to 190 mm (6-7 in.). The tail is 75-100 mm (3-4 in.) long and is usually a little long than the body-head length. The tail is paler below but not sharply bi-colored. The muzzle is pointed and the ears are relatively large and usually haired. General coloration is a brownish gray, but some house mice are blond or black. The belly fur is buff-white to dark gray.

Reproduction: 

House mice are the most prolific of our common rodent species. Under favorable conditions, mice can reach sexual maturity in 6 to 10 weeks. Female mice have a 4-7 day cycle with estrous lasting 12 to 14 hours. The gestation period is 18 to 21 days. They have between 5 to 11 litters per year with an average litter size of 4 to 7 pups. The male can have a breeding life span of 1 to 1.5 years, whereas the female’s lasts only 8 to 10 months.

Food and Feeding Habits: 

Mice are opportunistic and will try new foods. Unfortunately, their nibbling behavior decreases the possibility of taking a lethal dose of rodenticide bait at one feeding. Although they will sample new foods readily, they will return to old food sources after a few days unless the new food source has a higher preference. Where identical food sources are available, they eat at many places. Mice eat about 3 to 4 g of food a day. They usually feed at dusk and before dawn with bursts of feeding activity about 45 to 90 minutes apart. While water is no as essential to their survival as is the case for rats, mice will drink freely when water is available. Mice are omnivorous feeders but prefer seeds and grains. They like foods rich in protein and fats such as lard, butter, nuts, bacon, and meat, particularly in colder temperatures. They also like sweets such as sugar-water, candy, jam, cake crumbs, and chocolate. In wild habitats they eat grass, weed seeds, insects, and cereal grains.

Behavior and Habitat: 

Due to their small size, adaptability, and physiological adjustments, mice can us more divers habitats than rats. Mice have burrowed into meat carcasses in cold storage rooms. Nests built of burlap and feathers enable them to survive and even reproduce in extreme environments. Most mice in a given population are inquisitive. They have considerable smaller territories and may, for example, spend their life within a bag of dog food. A study in Wisconsin showed that the average distance traveled by mice was on 12 feet and 90 % of the trips were less than 30 feet. Unrelated mice in a social group are extremely aggressive towards each other. Most environments can support far more mice than one might suppose.

Evaluating Rodent Signs: 

Droppings are the most common rodent sign. They are usually found in secluded areas, near harborage, and in long runways. House mouse droppings are about 6 mm (1/4 in) long and are tapered. The size, shape and color of the dropping may vary considerable according to diet, and between young and old rodents in the population. Droppings can suggest facts about the population. If the droppings are fairly uniform in size, this indicated a more stable population, probable with only a few individuals. However, if the droppings vary considerably in size, this would suggest a growing population of young and old individuals. Colored droppings, such as red or green, occur most often from rodents eating rodenticide baits that are typically dyed to prevent confusion with animal feeds.

Black smudges along baseboards, rafters, and other heavily traveled routes indicate the presence of rodents. These rub marks come from the oils in the rodents’ hairs as they swing under rafters, run along common trails, or squeeze through openings. Gnawed areas may be apparent and will show the distinctive grooves made by the incisor teeth. Gnawed holes often appear in plastic bags, doorway areas, storage containers, etc. Dead carcasses that emit a distinctively unpleasant odor may also be an indication of the presence of mice. Dead carcasses may be hard to find as they could be in a crawl space or wall void.

Control:

Mice are very difficult to control where abundant food and cover are available. These supporting factors must be reduced or removed as much as is practical. Following is common methods of rodent control.

SNAP TRAP/MULTI-CATCH TRAPS/GLUEBOARDS: The common mousetrap baited with peanut butter or cheese will control small numbers of mice residing in homes. Traps can remove an animal from the premises without any potential odor problem. Traps can be used in sensitive areas such as food handling areas and residences with pets and/or small children. You must be knowledgeable of the rodent’s habits for proper placement and maintenance of this type of control. A dozen traps would be the minimum in a private dwelling, while 50 to 100 is not excessive for a warehouse or other commercial building. Under-trapping will increase trap shyness. The multi-catch live traps attract mice with their tunnel entrances and do not need to be baited. Like the snap-trap, it will offer a low hazard way of controlling mice and keep carcasses in known locations where they can be eliminated before decay and odor begin. Glue boards may also be used as an alternative to the rodenticide methods.

RODENTICIDES: Rodenticides are substances designed to kill pest rodents. Rodenticides come formulated as poisoned baits and as tracking powders (that rodents walk through and then digest after grooming). This method requires ingestion by the rodent and effectiveness depends on the size of the rodent with the amount of rodenticide ingested. This method requires locating the carcasses and removing, and most often odor will be present.

We have trained pest management specialists with the proper method of control for your home or business.

Information given above taken from the NPCA Pest Management Library- Vertebrate Pest Management Manual.