- Size: the head and body is seven to ten inches long with a tail that is an additional six to eight inches.
- Color: coarse brown fur with black hairs.
- Adult Norway rats can weigh between 7 and 18 ounces.
- Droppings are significantly larger than mouse droppings, approximately 3/4 inch in length with blunt ends.
Habits of Norway Rats:
- Sexual maturity is reached within two to five months.
- Females have three to six litters per year, with an average of seven to eight young per litter.
- Outdoors, rats nest underneath sidewalks and concrete, near buildings, and in areas with low ground cover.
- Indoors, rats nest in crawl spaces, basements, loading docks, and sewers.
- Rats forage up to 100-150 feet away from the nest and feed on meat, fish, and cereals. Rats also require a separate, non-food water source.
- Rats are generally shy and wary of new environments, including of newly placed traps.
Damage Caused by Norway Rats:
- A number of diseases have been associated with rats, including leptospirosis, which is spread through rat urine.
- Rat droppings and urine can contaminate stores of food.
- Rat excrement contains allergens that can trigger asthma in susceptible individuals.
- When living in close proximity with humans, foraging rats or those disturbed have been known to bite people. Some diseases can be transmitted through rat bites, but rats are not considered to be a host of the rabies virus.
- The tendency of rats to gnaw can cause structural damage as well as damage to wiring.
- Droppings, generally 3/4 inch in length with blunt ends.
- Damage from gnawing, including on wood, plastics, and wiring.
- Rub marks, where frequent travel routes have darkened deposits of grease from the fur of passing rats.
Exterior Rat Video
How to Control and Kill Norway Rats:
- Rat control requires the coordination of sanitation, exclusion, trapping, and sometimes baiting.
- Prevent access to food with thorough sanitation and storage of foods off the floor and in metal or thick plastic containers.
- Eliminate sources of moisture, which rats require for survival.
- Remove clutter and sources of harborage for rats to reduce possible nesting sites.
- Rat-proof the exterior and interior of a building by sealing all openings 1/2 inch wide or greater. Install door sweeps to prevent passage of rodents underneath exterior doors.
- Snap traps designed for rats are an effective means of eliminating established rats. Rats respond well to traps baited with meats or cereals. Snap traps are the preferred method to kill rats due to the ability to remove the rat and the opportunity to limit the use of pesticides.