House Mouse

The house mouse is the most commonly encountered and economically important of the commensal rodents, the Norway and Roof/black rats being the other two. House mice are not only a nuisance, they damage/destroy materials by gnawing, and eat and contaminate stored food. They also are of human health importance as disease carriers or vectors. The house mouse is thought to be of Central Asian origin, but now is found worldwide, including the United States.

Signs of infestation

1. Gnaw marks. New gnawings or holes tend to be rough, whereas old gnawings are smooth from wear.

2. Droppings. Fresh droppings are soft and moist, whereas old droppings are dried and hard; house mice's about 1/8-1/4 inch long, rod shaped, and with pointed end vs. American cockroach about 1/8 inch long and with ridges.

3. Track/footprints. The front foot is four-toed the and print is in front of the hind print with five toes. Fresh tracks are clear and sharp, whereas old tracks are at least partially obscured by dust.

4. Rub marks. These usually are less noticeable and smaller than those of rats.

5. Burrows. Indoors they often nest in various materials such as insulation. If burrows are active, they are free of dust and cobwebs. The entrance may be material packed, compressed, with rub marks sometimes visible.

6. Runways. Frequently mice use the same paths, usually along walls, stacked merchandise, etc. and to interior objects. Active runways are free of dust and cobwebs, with fresh droppings and tracks which may or may not be visible.

7. Damaged goods. Mice prefer seeds or cereals.

Habits

Mice are very social. Related males and females are compatible, but unrelated male mice typically are very aggressive toward one another. Social hierarchies with one male dominating lower-ranking males result in the maintenance of territories, which may include a large number of females as well as lower-ranking males, most of which will be related. All mature mice tend to show aggression towards strangers of either sex that enter their territory, which is marked with urine. Territory sizes vary but usually are relatively small. If food and shelter are plentiful, they may not travel more than 4-5 feet from their nests.

Mice are inquisitive. During the daily territorial patrol, they will explore anything new or changed, and establish new travel routes if needed. Mice are nibblers and eat only a small amount of food at any one time or place. Although mice will eat many kinds of food, seeds usually are preferred. There are two main feeding periods, at dusk and just before dawn, with many other "mini" feeding times in between. They will sample new foods but return to the old food unless the new food is preferred. Required moisture normally is obtained from their food, but they will take free water when available, especially when feeding on high-protein food when given a choice. They prefer sweetened liquids over plain water.