Rats can be a serious problem for homeowners. The following information can help you identify, control, and eliminate them. Some of the techniques can be applied to the common house mouse as well.

Rats have plagued mankind since prehistoric times. Their great ability to adapt to their environment and reproduce quickly has allowed them to survive over the centuries. Rats have been associated with infectious jaundice, bubonic plague, and typhus and are responsible for more human illnesses and deaths than any other mammal. Rats can carry as many as 35 diseases that can affect humans and livestock.

Signs of Infestation:

Most rats in the Midwest are Norway rats, which are burrowing animals. Any place outdoors could be a burrow as long as it provides shelter. Burrows are usually found in earth banks, dumps, sewers, along walls, under rubbish or concrete slabs, and in other similar places. They usually will only move in a 100- to 150-foot radius from their burrows in search of food and water. Burrows are typically three inches in diameter. If a burrow is in use, the entrance will be free of cobwebs and dust and there will also be fresh rub marks on hard packed soil. Fresh fragments of food or freshly dug earth at the entrance are also indicative of an active burrow. Capsule shaped droppings one-half to three-quarters of an inch long are evidence of rodent activity. Fresh rat droppings are moist, soft, shiny and dark. After a few days they will become dry and hard. Old droppings are dull and grayish and will crumble when pressed with a stick.

Since rodents frequently use the same pathway between food, water and shelter, their runways can be observed by grease marks or by beaten earth that has been swept clear of debris. Another method of detection is looking for tracks. Five-toed tracks from the rear paws are more often found than four-toed tracks from the front paws.

Tail marks, too, are often visible. Dusting materials such as talc or flour are useful when checking for rodent activity.

Rats have poor vision and rely on their senses of smell, taste, hearing and touch. They have sensitive whiskers and also specialized hairs called guard hairs. They prefer to keep these hairs and whiskers in constant contact with a vertical surface as they move about in order to protect and familiarize themselves with their environment. By doing so, they leave dark and greasy rub marks along their runways near the ground or floor level. When fresh, these grease marks will smear. As they age, they gather dust and dry and will flake off when scratched with a fingernail.

Physical Characteristics:

The Norway rat, also known as the barn rat, brown rat, gray rat, sewer rat, and wharf rat, has coarse fur that is usually reddish brown to gray. A Norway rat will reach sexual maturity in three to four months. As an adult, its body length is 7 to 10 inches, and it averages one pound in weight. Rats usually live for one year. A female rat will have approximately 20 offspring per year. Rat breeding periods peak in the spring and fall.

Rats have four front incisors that grow six inches a year. It is necessary for rats to gnaw to keep these teeth short and sharp. Rats will gnaw to gain entrance to obtain food. Rats are nocturnal, usually feeding right after dark and again before dawn. If they are overcrowded, then they will come out during the daytime in search for food and water.

Rodent Control:

Here are some helpful hints for controlling a rodent population. Disrupting their environment by moving items that border their runways or putting broken glass down their burrows could cause their departure.

Snap traps (3"x7") and box traps are also good control devices. These can be purchased from most home improvement stores. Peanut butter, nutmeats, doughnuts or any other protein food make good bait. It is important that the traps are placed in the rodents' pathways. Force the rats to pass over the trigger by creating obstacles. Two or more traps placed closely together produce the best results. These should be kept in the same place for at least three days before moving them to another location.

Rodenticides are easy to use and are effective for controlling rodents, but should be used with great caution if there are pets or children in the area. For this reason, the preferred type to use is an anti-coagulant - which prevents the rodent's blood from clotting. These are distinguishable from other rat poisons by containing one of the following ingredients: Brodifacoum, Bromadiolone, or Diphacinone. Be sure to follow the manufacturer's directions and cautions when using. In order for the anti-coagulant to be effective, the rodent must ingest it for several days. The rat will not become bait shy, which often happens with single dose rodenticides, because they will not associate their weakening condition with the anti-coagulant laced bait. Eventually the rat will die of internal hemorrhaging.

Property owners should "rodent proof" their buildings by eliminating entry and keeping their property free of garbage and refuse and any other items that would provide food, water or shelter.

All cracks or breaks in the foundation walls should be repaired as well as gaps where pipes and wires enter or exit the structure. Windows and doors should fit tightly. All garbage and refuse should be stored in galvanized rust resistant containers with tight fitting lids. Dumpsters should be kept closed at all times. Grass should be mowed frequently around storage and building areas and the grass clippings stored properly and removed promptly. Any item stored outside (particularly wood for gnawing) should be kept 18 inches above the ground. Stacks of papers, books, boxes or other items should be stored away from a wall. All areas which can impound water should be eliminated. All pet food should be kept indoors. All bird feeders should be removed if rodent activity is detected, and any spillage cleaned up.

City Nuisance Ordinance Requirements:

According to the Overland Park Municipal Code Chapter 7.04 (Nuisance Ordinance) it is unlawful for any property owner, representative, tenant, or other such person with control, occupancy, or possess of real property to allow an infestation of rodents on any parcel of land within the City. If the person responsible for the property, after being served a notice of abatement, fails to comply or request a hearing, the city can go onto the property to abate the violation. The associated costs of the abatement and administrative fees could be charged to the property owner. The property owner could be subject to receive a Notice to Appear in Municipal Court for failure to correct the violation.

Rat Facts:

• There are an estimated 200 million rats in the United States - nearly one rat for every person!
• A rat can gain entrance through any hole larger than a half-inch in diameter.
• A rat can gnaw through wood, plaster, plastic, lead pipe, aluminum, cinder block, porous concrete, adobe brick, metal conduit, soft rubber, cardboard, paper and cloth materials.
• When a rat gnaws or chews, it can exert a force of approximately 24,000 pounds per square inch.
• A rat can fall 50 feet without serious injury.
• A rat can jump 3 feet vertically and 4 feet horizontally from a flat surface and reach upward 18 inches.
• Rats can climb bricks, trees, vines, horizontal or vertical wires or other rough exteriors that provide footholds.
• Rats can climb the outside of any vertical pipe that is within 3 inches of a wall or support.
• Rats can climb the inside of vertical pipes from 1 to 4 inches in diameter and outside vertical pipes up to 3 inches in diameter.
• Rats can tread water for three days and can swim in open water up to one-half mile, against swift currents, through floor drains and toilet bowl traps.
• Rats are colorblind and can only see for several feet, but their senses of smell, taste, hearing, and touch are acute.
• One pair of rats could have 15,000 descendants in a year.