Body: brown, with white belly, but can vary (see below)
A small, scaly-tailed mouse with a distinct notch in the cutting surface of upper incisor. ); hair short; ears moderately large and naked; upperparts ochraceous, suffused with black; belly buffy white, or buffy, usually without speckling and with slaty underfur; yellowish flank line usually present; tail brownish with black tip, not distinctly bicolor, but paler on underside; ears pale brown, feet drab or buffy, tips of toes white. External measurements average: total length, 169 mm; tail, 93 mm; hind foot, 18 mm. Weight of adults, 17-25 g. As commensal animals, house mice live in close association with man — in his houses, outbuildings, stores, and other structures. Where conditions permit, feral mice may be found in fields, along watercourses, and in other places where vegetation is dense enough to afford concealment. Although largely nocturnal, house mice are moderately active during the day, chiefly in their quest for food. As commensals, house mice feed on practically any type of food suitable for the use of man or beast
Body: brown, similar to the Roof Rat, but larger and chunkier; tail shorter than length of head and body
The Norway Rat lives both as a communal in close association with man and in the feral state. As a communal this rat lives principally in basements, on the ground floor, or in burrows under sidewalks or outbuildings. They feed on a variety of items including both plant and animal materials. All sorts of garbage appears to be welcome, but their main stay is plant material. Grains of various sorts are highly prized. These rats are prolific breeders. The gestation period varies from 21 to 23 days and the number of young from two to 14, averaging seven or eight. the Norway Rat is destructive to property and foodstuffs. Also, it plays an important part in the transmission of such human diseases as endemic typhus, ratbite fever, and bubonic plague.
Body: A blackish (or brownish), medium-sized, slender rat with long, naked, scaly tail; tail usually longer than head and body but not always so.
Total length, 370 mm; tail, 190 mm; hind foot, 36 mm. Weight, up to 200 g. Roof rats are largely commensals and live in close association with man. They seldom become established as feral animals as do the Norway rats. They may live near the ground, but usually they frequent the attics, rafters, and crossbeams of the buildings. They make typical runways along pipes, beams or wires, up and down the studding, or along the horizontal ceiling joists, often leaving a dark-colored layer of grease and dirt to mark their travelways. Like the Norway rat, the roof rat is largely nocturnal and only where populations are relatively high does one see them frequently in the daytime. They accept a wide variety of food items, including grains, meats, and almost any item that has nutritive value. Like the Norway rat, the roof rat is destructive to property and foodstuffs. Also, it plays an important part in the transmission of such human diseases as endemic typhus, ratbite fever, and bubonic plague.