Facts: Excellent swimmers and can stay submerged in water for up to three minutes
Appearance: Brown, heavy-bodied, six to eight inches long; small eyes and ears, blunt nose; tail is shorter than head and body; fur is shaggy; droppings are capsule-shaped.
Habits: Nest in underground burrows, from which they enter buildings in search of food; tend to remain in hiding during the day.
Diet: Omnivorous, but prefer meats; cannot survive long without water.
Reproduction: Reaches sexual maturity in two months; can breed any month of the year; litter may number from eight to twelve; females can have four to seven litters per year; adults live as long as one year.
Other Information: Most common rat in U.S.; limited agility, but excellent swimmer; carrier of many serious diseases.