The natural habitat of wild mice and rats includes forests and grasslands, and a variety of species are found from sea level to high mountain elevations.

Known as "commensal", meaning "living at the same table," mice and rats have had a long history of living close to people. Fossil records place evidence of house mice in a Neolithic Turkish community over 8,000 years ago. Their spread coincided with the construction of houses and barns which provided them shelter, with the development of agriculture, which provided them with food, and with ship travel, which provided them with transport over water.

Wild mice and rats are omnivores, eating a variety of vegetable matter, insects, and meat. Commensal rodents feed on any human food available as well as bird seed and pet food.

Mice range in color from pale gray to brown, usually with lighter sides and underparts. Domestic strains of house mice are predominantly white with black or gray markings.

House mice build loose nests of shredded paper and fabric behind rafters, in woodpiles, in storage areas of other hidden areas where there is a nearby source of food. They breed continuously and have five to ten litters per year. Litters average five to six young, born blind and without fur. Fully furred after ten days and weaned at about three weeks, mice reach sexual maturity between five and six weeks. Generally, there is a high mortality rate of young mice, and the average life span of adults is one year.

The most common species of commensal rats are Norway and roof rats. Both are found in urban and suburban areas where they have reliable sources of food and shelter.

Norway rats are ground dwellers, and are likely to inhabit cellars, basements, and lower floors of buildings. Because they swim and dive well, they can survive in sewers.

Roof rats are distinguished from Norway rats by their darker color, slender bodies, pointed muzzles, and tails that are longer than their heads and bodies. As their name implies, they are agile climbers and are often found on roofs and on the upper levels of buildings.

Commensal rats may reproduce one to twelve litters in a year with average litter size of eight to nine. The young leave the nest at about twenty days, and they reach sexual maturity at two to three months.

Because they are gnawers, mice and rats can cause damage to buildings, especially when they claw through insulation and wiring. Rodents are attracted to stored food, especially grain and seed, and they can contaminate it with their urine and feces. With habitat modification, property owners can discourage and exclude mice and rats.

Remove all available food sources that might attract rodents. Store food in secure containers, and dispose of garbage in a metal can. Make sure the lid fits tightly. Do not put food of any kind in open compost piles; bury food waste in an underground composter or use a lidded worm box instead.

Rodents are also drawn to pet food. It is best not to feed cats and dogs outside, but, if you have no other alternative, pick up bowls and leftovers promptly. If you feed birds, store seed in secure, metal containers. Put only as much seed in feeders as will be eaten in a day, and clean up spilled seed and hulls immediately.

Modify outdoor habitat and eliminate shelter sites by mowing long grass, removing weeds and brush, and trimming shrubs at ground level. Remove debris and wood piles close to buildings.

Rodents can enter buildings through holes no bigger than 1/2 inch in diameter and they can usually climb interior walls. Stuff steel wool into cracks and around drain pipes and other small openings, and seal with caulking or cement. Use hardware cloth of 1/4 inch squares or smaller to patch larger holes, to screen all vent openings, and to skirt building foundations at least 12 inches underground. Be sure to seal all holes and cracks in walls, eaves, and roofs.

Live-trapping and release is a more humane way to remove mice and rats than glue traps, poisoning, or snap traps. However, live-trapping is not a long term solution and must be accompanied by thorough rodent-proofing as described above.

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