RATS

The Norway rat (Rattus norvegicus) (also known as the common brown rat) is a destructive pest. Found in and around towns and farms throughout North America, these rodents eat and contaminate large amounts of feed, damage structures by their gnawing and burrowing, and spread diseases that affect livestock and humans.

Recognizing Rat Infestations

Rats can be detected by their droppings or evidence of fresh gnawing. Tracks can be seen in mud and on dusty surfaces. Burrows and runways may be found next to buildings, along fences, and under low vegetation and debris.

Rat Facts

Norway rats are robust rodents that usually weigh about 11 ounces. Adults are 13 to 18 inches long, including a 6- to 9-inch tail. Their fur is coarse, brownish, and scattered with black hair on the upper surfaces. The belly fur is typically gray to yellowish-white, and they sport a naked, scaly tail.

Rats will eat nearly anything, but they prefer high-quality foods such as fresh grain, livestock feed, and meat. Rats require 1 fluid ounce of water daily when feeding on dry food.

Rats have keen senses of hearing, smell, taste, and touch. They will climb to find food or shelter, and can gain entrance to a building through any opening larger than 1/2 inch in diameter.

Rats have litters of six to 12 young, which are born 21 to 23 days after mating. Young rats are sexually mature in about three months. Breeding occurs mostly in spring and fall. The average female has four to six litters per year. Individuals usually live 12 to 18 months.

Sanitation

The presence of garbage and other refuse allows rats to exist in residential areas. Good sanitation will not eliminate rats under all conditions, but will make the environment less suitable for them to thrive. This involves proper storage and handling of food materials and refuse, and elimination of rodent shelter.

It is difficult to remove all food rats can use on farms where food grains are handled and stored, or where livestock are housed and fed. In such situations, you can still remove the shelter rats use for hiding, resting, and nesting.

Warehouses, grain mills, elevators, silos, and corn cribs are especially vulnerable to rodent infestation. Store bulk foods in rodent-proof buildings, rooms, or containers whenever possible. Stack packaged food on pallets with adequate space left around and under stored articles to allow rat inspections.

Rodent-proof construction

The most successful and permanent form of rat control is to 'build them out' by eliminating their access to structures. Ideally, all places where food is stored, processed or used should be rodent-proofed.

Seal any openings larger than 1/4 inch to exclude both rats and mice. Openings where utilities enter buildings should be sealed tightly with metal or concrete. Wood, plaster, and caulk will not keep rats out. Equip floor drains and sewer pipes with tight-fitting grates that have openings less than 1/4 inch in diameter. Doors, windows and screens should fit tightly. It may be necessary to cover edges with sheet metal to prevent gnawing.