Like the Norway and black rat, the house mouse is not native to North America, but was introduced by human explorers in the 16th and 17th centuries. Mice are not as large or considered as dangerous as rats, but they can still cause considerable damage by consuming large quantities of food, chewing through almost any material (such as wood, fabric, even electrical wires) and spreading diseases. They have also been known to invade cultivated fields, feeding on seeds and insects.

House mice are usually around 6 inches in length, grayish-brown above and slightly lighter gray beneath. They frequently become a problem in fall and winter when they move indoors as the weather grows cold. Signs of intrusion in the home include small dark droppings, holes in insulation and shredded nesting materials. Since mice are prolific breeders, sometimes producing as many as 17 litters in a year, it's a good idea to treat an infestation early, using mechanical traps or the more effective bait killers labeled for use in the home.