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Pest Facts

Looking for information about common pests invading your home or business?

Kirchner's Pest Control has the answers! Check out our pest facts below or feel free to contact us about your pest problems!

Kirchner's Pest Control offers one-time treatments and complete maintenance plans to keep your home, store or facility pest free!


Physical Characteristics / Threat Level

Ants are characterized by the narrow connection (the pedicel) between the thorax and abdomen of their bodies. Elbowed antennae also distinguish ants from other insect species. Four species of ants are common in Pennsylvania including pavement ants, black carpenter ants, larger yellow ants, and thief ants. The most common household ant is the pavement ant that has a blackish brown body and grows to 1/10" long. Ants are not considered dangerous to humans and most pose no property threats, except for carpenter ants.

Where They Live

All ant species are social and live in colonies made up of a queen, worker ants, and males. The colony lives in an ant hill or nest, usually outdoors. The colony can adjust to seasonal changes in temperature and humidity by moving up or down in the ant hill or nest. In warm climates or when colonies are established indoors, ant colonies may be constantly active.

What They Eat

Ants commonly feed on seeds, plant sap, honeydew, table crumbs, grease, meats, and dead insects.

Physical Characteristics / Threat Level

Bed bugs are oval, chestnut brown insects that appear flattened from top to bottom. Adult bed bugs measure about 1/4" in length. Bed bugs live about 4 months, but are capable of hibernating up to 18 months in the right conditions. Bed bugs lay approximately 3 eggs per day once mature, and are often brought in on people with an existing population and their possessions. While bed bugs are not considered to be disease carriers in North America, their bite can produce irritating itching and burning sensations. The act of biting is usually not felt, but an allergic reaction often develops at the bite location from the protein found in the bed bug's saliva.

Where They Live

Bed bugs often enter homes via second hand articles and furniture. They may also migrate between homes via wires, plumbing or rain gutters. Bed bugs hide in cracks and crevices in walls, floors, beds and furniture. When only a few bed bugs are present, they live close to human sleeping areas. When numerous, they can be found in many rooms of a home or business. Bed bugs are active only at night, usually just before dawn. Mated female bed bugs deposit their eggs in resting places. One female will produce about 345 eggs during her lifespan.

What They Eat

All members of the bed bug family feed on the blood of birds or mammals. The common bed bug, attacks humans, but there are other species which attack bats, pigeons and rodents. Adult bed bugs feed about once a week on average.

Physical Characteristics / Threat Level

Adult boxelder bugs are black with red or orange markings and are about 1/2" long. Their wings lay flat across their bodies forming an "X" shape. Immature nymphs are only 1/16" and appear bright red when they hatch. Boxelder bugs are harmless, but can bite if mishandled. They are generally harmless to property, though in large numbers their excrement can leave stains on walls, curtains, or other surfaces.

Where They Live

During the autumn months, adult and larger nymph boxelder bugs congregate in large numbers, primarily on the bark of boxelder trees, then begin migrating to a place for overwintering. Only adults overwinter, moving to hibernation sites. Boxelder bugs hide in cracks and crevices in walls, in door and window casings, around foundations, in stone piles, tree holes, and other protected places. On warm days they appear on light painted outdoor surfaces on the south and west side of the building, gathering heat from the sun.

What They Eat

Boxelder bugs feed primarily on the seed-bearing boxelder trees by sucking sap from the leaves, tender twigs and developing seeds. Some also feed on maple, ash, plum, cherry, apple, peach trees or grapes, causing scarring or dimpling of fruits. However, they seldom develop in large enough numbers to become a nuisance unless able to feed on pod-bearing boxelder trees.

Physical Characteristics / Threat Level

Carpet beetles are small, flying insects that belong to the Dermestidae family. If found in homes or buildings they should be controlled since they will damage fabrics.

Where They Live

Since they fly, carpet beetles may be found throughout a home or building, not necessarily near a food source. Adult beetles are attracted to light and may be found crawling or dead on windowsills. Larvae avoid light and are usually found in the materials on which they are feeding.

What They Eat

These beetles attack a variety of substances such as fabrics, particularly those of animal origin such as wool, silk, hair, feathers, and furs. They will attack synthetic materials if they are soiled. The also feed on most stored foods. When outdoors, carpet beetles feed on flower pollen.

Physical Characteristics / Threat Level

House centipedes grow to 1 1/2 inches in length and have 15 pairs of long, slender legs that are encircled by dark or white bands. The bodies of centipedes are typically brown to grayish-yellow with three dark strips along the top. Centipedes are harmless and pose no danger to people or animals.

Where They Live

Centipedes can be found both indoors and outdoors and prefer to live in damp areas. In homes or buildings they are typically found in the basement, closets, or the bathroom. They can also be found beneath homes or buildings in un-excavated areas. Centipedes also live under the bark of firewood, so they are often carried into homes on firewood logs.

What They Eat

Centipedes feed on small insects, spiders, and the larvae of insects, so they are considered a beneficial pest.

Physical Characteristics / Threat Level

In the larval stage, clover mites are bright reddish-orange and have six legs. After the larvae feed, their body color changes to dark green. Clover mites do not bite people, transmit disease or destroy property.

Where They Live

Mites seek cracks and crevices in mortar, beneath the clapboard siding and window ledges, or under tree bark, where they lay eggs and molt. In spring, fall, and sometimes during warm spells in winter, homes and buildings with flourishing lawns are invaded by clover mites.

What They Eat

Clover mites feed on grass, clover, and lawn weeds growing near the foundation of homes and buildings or near the bases of lawn trees.

Physical Characteristics / Threat Level

German cockroaches are the most common roach infestation in Pennsylvania. Adult German cockroaches are 1/2" to 5/8" long, tan to light brown with fully developed wings, though they do not fly. Other common species of cockroaches found in Pennsylvania include the American, Oriental, and brown-banded cockroaches. The relatively wide and flat body of most cockroach species enables them to move in and out of cracks and narrow openings with ease. Cockroaches are suspected disease carriers. Laboratory tests have shown that they may play a role in spreading food poisoning agents such as salmonella. Other pathogenic organisms have also been associated with cockroaches.

Where They Live

Cockroaches have been present on Earth for approximately 300 million years and have adapted to live with humans. During the day they hide in cracks, crevices and other dark places. Cockroaches avoid light, thus they are most active at night.

What They Eat

Cockroaches are excellent scavengers and will feed on practically every type of food which humans consume, including sweet, fatty, and starchy substances in soft drinks, beer, cereals, soap, dried fruit, meat products, cheese, bread and other pastry products, cooking fats and oils, pastes, glues, leather, soiled books and other plant and animal products. Garbage is also a primary food source for cockroaches.

Physical Characteristics / Threat Level

Earwigs are reddish-brown to black insects, about 1/2" long with a pair of tweezer-like projections at the back of their bodies. They do not, as the their name implies, work their way into people's ears. They do not bite, but some of the larger ones can pinch with their tweezers. Young earwigs resemble the adults, but are smaller and lighter in color.

Where They Live

Earwigs are normally found outdoors but some do wander inside homes and buildings.

What They Eat

Earwigs feed on decaying plant material, but they may also feed on other insects or attack healthy plants.

Physical Characteristics / Threat Level

Adult fleas are up to 1/8 inch in length and appear reddish brown to black. Flea larvae are hairy and wormlike and appear up to 3/16 inch long. The larvae have no eyes or legs. Fleas are considered spreaders of infectious disease and some species have been linked to plague bacillus, often transmitted by the fleas of rats to humans.

Where They Live

Adult fleas live on their hosts - household pets, rodents, or other mammals. Some species of fleas can live on humans. Female fleas lay eggs on their host that fall to the ground and usually hatch within 2 days. Fleas and their larvae thrive in warm conditions with humidity levels of at least 75%. The larvae stage lasts 5-15 days, when larvae spin cocoons in protected areas throughout their environments such as floor crevices, carpet fibers, or outdoor areas free of rain or other disturbances. New adults emerge from the cocoons in 2 weeks. If conditions are unfavorable, developing fleas can remain in their cocoons for up to a year before hatching. Adult fleas live 4 to 25 days.

What They Eat

Adult fleas feed on the blood of their hosts, using piercing mouth parts to extract small amounts of blood. Flea larvae feed on skin flakes, dandruff, and grain particles found on the floor or ground around them.

Physical Characteristics / Threat Level

Common house flies are easily identified by the four dark, longitudinal stripes on the top of their thorax, or middle body region. Flies vary in length from 1/8" to 1/4". Their mouth parts are adapted for sponging up liquids. They cannot bite. House flies are strongly suspected of transmitting at least 65 diseases to humans including typhoid fever, dysentery, cholera, poliomyelitis, yaws, anthrax, tularemia, leprosy and tuberculosis.

Where They Live

The eggs of house flies are deposited into decaying matter (grass clippings, garbage, human and animal excrement). Horse manure is their preferred breeding medium. Eggs hatch within 7 1/2 hours when temperatures are high (99 degrees F), but may take 2 days if temperatures are only 59 degrees. Eggs hatch into wormlike creatures called maggots that feed on the material where they hatch. Mature larvae stop feeding and burrow for protection in drier surrounding areas, where they pupate. Adult flies mate within one to two days after emerging from their pupal cases. House flies normally live about 2 1/2 weeks during the summer, but can survive up to 3 months at lower temperatures. Flies normally stay within 1/2 to 2 miles of their point of origin.

What They Eat

Flies can only ingest liquid food. They feed on fecal matter, discharges from wounds and sores, sputum, and all sorts of moist, decaying matter such as spoiled fish, eggs and meat. Flies require lots of water since they are continually salivating and voiding liquids.

Physical Characteristics / Threat Level

House crickets are most often identified by their song or chirp that is produced by the adult male. Nymphs and females cannot sing. House crickets are not usually present in harmful numbers, but their chirping is often considered a nuisance.

Where They Live

Outside, house crickets may be found in decaying refuse where the heat of fermentation may provide warmth to speed their lifecycle. House crickets develop most rapidly at temperatures near 90 degrees F. A generation is completed in two months to one year, depending on available food and temperature. In years when temperatures are high and other conditions are favorable, house crickets may breed in great numbers and invade houses, crawling through poorly fitted windows or under doors. Large migrations, particularly between July and October, can often be traced to large refuse dumps or poor sanitation practices.

What They Eat

Crickets feed on rubbish, bread products, fruits, vegetables, cereal products, dead animals, meat products, and dog food. Some may attempt to feed on paper, paper products, woolens, cotton and silk textiles, and leather products.

Physical Characteristics / Threat Level

House spiders vary in size and appearance, but all have 8 legs. Most spider species are harmless to humans and do not destroy property. However several species of jumping and wolf spiders are capable of inflicting minor bites to humans.

Where They Live

Many spider species live in human dwellings. The common house spider, the common sheet web spider, and the long-bodied cellar spider are commonly found in basements. Jumping spiders are common on the outside walls of houses and often stray inside. A number of species of crab spiders are brought into homes in the summer on bouquets of flowers. In the summer and fall, many spiders are carried into homes on laundry that was dried outdoors.

What They Eat

Spiders eat insects and some also consume other spiders.

This category of pests consists of various types of small arthropods, some of which bite. Found just about everywhere, some species of mites are harmless, while others are parasitic, such as bird mites and rodent mites, which feed on the blood of the species they inhabit.

Most mites travel by walking, but can sometimes be carried to other locations by the wind. This is especially true in locations with nearby farm fields.

Most mites are not a threat to humans, but are capable of staining siding and doors, which makes them a nuisance pest.

Physical Characteristics / Threat Level

Mosquitos are insects with one pair of wings. Adult mosquitoes have a long proboscis and females can penetrate the skin of animals. Mosquitoes have scales on their wings and over their bodies. The wing is characterized by a single short vein located between two branched veins. Mosquitoes are known vectors of human disease including malaria, yellow fever, filariasis, dengue, and encephalitis. They can also transmit disease to animals, heartworm to dogs, for example.

Where They Live

Mosquitoes are found all over the world from the tropics to the Arctic. 160 species of mosquito exist in North America and 49 species have been recorded in Pennsylvania. Mosquitoes undergo complete metamorphosis: egg, larva, pupa, and adult. Most mosquito species lay their eggs in or near water. In fact, any receptacle which can trap water can be an important source of mosquitoes, which can include tree holes, depressions in soil from tire tracks, animal footprints, or birdbaths, or water trapped in the axils of leaves. An estimated 7000 mosquitoes can be found in 1 square foot of water.

What They Eat

All female mosquitoes except for Genus Toxorhynchites, feed on blood. Their prey varies with the species, with some feeding on mammals, others on birds, reptiles, or amphibians. Adult males and females feed on nectar and plant juices. Males do not feed on blood because their mouthparts are not rigid enough to penetrate animal skin.

Physical Characteristics / Threat Level

Because of the long, slender appendages at the rear of their abdomen, silverfish and firebrats are often called bristletails. These insects have long antennae and are wingless. Firebrats are brown. Silverfish are silver gray. Firebrats are covered with tufts of bristles and silverfish are not.

Where They Live

Outdoors, both silverfish and firebrats live beneath the bark of trees, under debris, and in forest shelter in warmer areas of the state. Indoors silverfish and firebrats are often discovered in bathtubs or wash basins. These insects usually fall into the sink or tub and then are unable to climb back out. Silverfish and firebrats are readily introduced into homes and buildings via cartons, papers, books, and magazines moved from one place to another. They can also move long distances along heating pipes in conduits and plumbing in homes or buildings. Under favorable conditions, silverfish complete their life cycle from egg to adult in 3 to 4 months. Adults can live for several years.

What They Eat

Silverfish and firebrats feed on cereals, flour products, glues used in book bindings, wallpaper, linen, starched cotton and other fibers, certain wall insulation materials, and other paper products.

Physical Characteristics / Threat Level

Sowbugs and pillbug are not insects, but crustaceans. They are relatives of crayfish, crabs, and shrimp. Both are similar in appearance and behavior, however pillbugs roll up into a small ball or "pill" and sowbugs do not. Sowbugs and pillbugs are harmless and do no damage to homes or buildings.

Where They Live

Sowbugs and pillbugs are often found on porches, in basements and in other areas in homes and businesses. Sowbugs and pillbugs need a moist habitat to survive. As a result, in hot weather they will invade homes or buildings in search of moisture when the debris under which they live becomes too dry. Wet weather can also force them out of their living areas and cause them to migrate indoors. Sowbugs and pillbugs become inactive during cold weather except those living in heated structures.

What They Eat

Sowbugs and pillbugs feed primarily on decaying vegetable material. Occasionally, when they are numerous they can damage growing plants.

Physical Characteristics / Threat Level

Springtails are primitive insects that have jumping organs located on the rear of their abdomens that propel them into the air.

Where They Live

Springtails require very moist conditions and do not tolerate light. The many species of springtails have different humidity, temperature, and food requirements.

What They Eat

Most species of springtails feed on plant and animal debris. Some species are plant pests. Some are active on snow during winter and are called "snow fleas".

Physical Characteristics / Threat Level

Of the 20 known species of ticks in Pennsylvania, four are numerous including the American dog tick, the deer tick, the brown dog tick, and woodchuck tick. All ticks are parasites that feed on certain species of mammals, birds, and reptiles. Ticks are known to transmit several important diseases to humans, domesticated animals and wildlife.

Where They Live

Female ticks lay eggs in sheltered hiding places. When young ticks emerge, they must find a host on which they can feed. After feeding, young larval ticks drop off the host to molt.

What They Eat

Ticks feed on the blood of their hosts. Ticks leave the host during each growth stage, but must find a host to complete their development. Some ticks can survive many months to a year or more without feeding.

Physical Characteristics / Threat Level

Yellow jackets are a species of wasp, about 1/2” to 1” long and can be identified by their black and yellow color pattern. They are not overly aggressive unless provoked, but they are capable of stinging multiple times.

Where They Live

Yellow jackets are social insects that live in nests or colonies made of paper-like material. Eggs hatch from cells within the nest. Nests are commonly found underground, via a small hole in the dirt, in trees, or in small entry points along a building’s foundation or soffit line. Each nest varies in size from 300-120,000 cells. Nests begin forming in summer and grow through early fall. If a nest entry point is sealed/caulked prior to control of the colony, there is a high risk of driving the colony further inside the structure. Only inseminated (pregnant) females survive the winter, hiding in sheltered places.

What They Eat

Yellow jacket workers feed primarily on nectar, other sugary solutions, and ripened fruit during the latter part of the summer and into fall. Workers feed the developing larvae chewed-up insects.

Physical Characteristics / Threat Level

Cicada killers are a species of wasp that look similar to yellow jackets, but are much larger, measuring 1 1/2" in length. Most cicada killers are extremely passive and only sting when stepped on.

Where They Live

Cicada killers are solitary creatures and do not share their nest with other cicada killers. They nest in the ground, typically on soft hillsides that see sunlight. Little mounds of dirt can be observed around the entrance to their nest.

What They Eat

As their name suggests, cicada killers kill cicadas, dragging them into their nest. Eggs are then deposited into the body of the preserved cicada and the larvae feed on the cicada's body. The larvae mature, overwinter, pupate in spring and emerge the following summer.

Physical Characteristics / Threat Level

The two main species of hornet are the European and the Bald-Faced hornet. European hornets are brown with yellow abdominal stripes. Bald-Faced hornets are mostly black with a white head. Both species of hornet are very aggressive and will sting if they feel a threat has come too close to the nest.

Where They Live

Hornets are large, social insects that live in aerial nests, often formed in trees, or alongside structures in areas that see sunlight and are protected from rain. Their nests are similar in structure to those of the yellow jacket, paper-like and made up of 2000 to 3500 cells in a honeycomb structure. Nests usually appear in late summer, growing larger through the season. Nests are guarded by a “scout” that watches for possible threats.

What They Eat

Much like yellow jackets, hornets feed on nectar, other sugary solutions, and ripened fruit during the latter part of the summer and into fall.

Physical Characteristics / Threat Level

Wasps are brown with yellow markings and long legs. Most wasps are only mildly aggressive.

Where They Live

Semi-social, wasps live in small colonies. Wasp nests contain a single layer of paper comb that is always exposed, never covered. Nests are located in trees and shrubs, often hidden, or high along structures in places that see sunlight and are protected from rain.

Physical Characteristics / Threat Level

Bumble bees are ground-nesting, social insects with large, fat bodies that are black and yellow in color. Bumble bees look very similar to Carpenter bees, but can be distinguished by the hairs on the upper part of their abdomens. Bumble bees sting in defense of their nest and can sting several times.

Where They Live

Bumble bees overwinter underground and emerge when spring blooms appear. Queens search out abandoned mouse nests and similar places which they repair to use as nest sites. By autumn, the population of the bumble bee colony can reach several hundred bees.

What They Eat

The queen forages for nectar in order to rear the first brood. Thereafter, she specializes in egg production, while young workers do the field work.

Physical Characteristics / Threat Level

Honey bees are generally considered beneficial because they produce honey and wax, and they pollinate many species of fruit, vegetables, and hay crops.

Honey bees generally don’t sting unless they are threatened. Worker honey bees are unable to withdraw their imbedded stinger from their victim, so can only sting once.

Where They Live

Swarming is a natural part of the lifecycle of a honey bee colony. In Pennsylvania, most swarming begins in May and continues into early summer. Prior to swarming, cells are prepared which will produce a new queen bee. The swarm usually settles in a tree or a similar place until the scout bees locate a suitable nesting site. Trouble can start if the swarming bees choose an active area near a home or public building.

Sometimes honey bees establish their colony in the walls of a house or other structure. It’s important to have the honey bees removed by a beekeeper before they become established. If bees are killed with an insecticide after they’ve begun to produce wax and honey, the wax and honey can drip and damage the appearance of both the inside and outside of the structure. Wax moths, mice, and carpet beetles may breed in the debris and feed on the dead bodies of the bees.

Larvae from a variety of species feed on dried food products (rice, cereal, oats, pet food, grains, etc). These dried products can also serve as harborage for pests, making them difficult to treat. Some pests create a webbing in and around the source of the contamination. Adults eat their way out of the dried food products and packaging and begin infesting other dried food products in the vicinity.

The best course of action is to locate any contaminated products and remove them from the premises. Keeping all remaining grain products in sealed containers can help prevent any remaining pests from re-infesting clean foods.

Physical Characteristics / Threat Level

Mature adult termites are black in color, have wings, and well developed compound eyes. All termites have six legs. While flying ants have a similar appearance to many termite species, the abdomen of a termite is about the same width from front to rear, whereas flying ants have a constricted waist. Swarmer termites are about 1/2" long. Worker and soldier termites are about 1/4" long. Subterranean termites cause more damage to buildings in the United States than any other insect. Pennsylvania is within a region of moderate to heavy termite infestation. The discovery of primary reproductives or swarmer termites is usually the first indication of termite infestation.

Where They Live

Termites are social insects that live in colonies. Each colony lives in a caste structure consisting of reproductive, worker, and soldier members. Termites establish their nests in soil and worker termites build tunnels to buried wood or to the surface where they find wood in trees or homes. Growth of a new termite colony happens slowly and begins with the queen, who lays her eggs after mating. At first only workers are produced. Soldiers are produced next to defend the growing colony. Primary reproductives are produced about 5 to 6 years after the colony is founded. Heavy damage from subterranean termites usually does not occur until 8 to 10 years after the founding of the colony.

What They Eat

Termites eat wood, though they are unable to digest cellulose, the primary component of wood. To aid in the digestion process, termites host one-celled organisms called protozoa in their guts. The protozoa digest the cellulose and produce waste products that the termites can ingest.

Wood infesting beetles bore into wood where they lay their eggs. Eggs are commonly deposited into the wood prior to construction, and can take years to hatch out. Once eggs mature, first to larvae then to adults, they bore to the surface. This emergence leaves a series of tiny "pinholes" within the wood structure and is evident by the sight of to a fine wood powder. This powder is often how the wood infesting beetles are discovered.

Often, infesting beetle evidence is inactive and needs no treatment. The best way to monitor activity is to sweep up the fine wood powder. If new wood powder forms, the site is still active.

Physical Characteristics / Threat Level

Carpenter ants are a large black ant species varying in size between 1/4" to 1/2" in length. A single node is present on the pedicel and its body is divided into 12 segments. These ants also have antennae. Ants are harmless to humans, but do pose a property threat since they can damage wood inside homes and buildings.

Where They Live

Carpenter ants are native to Pennsylvania and can primarily be found in trees and wooden structures. They excavate wood to build their nests, creating smooth tunnels. Ants enter homes and buildings through cracks around doors, windows or through holes created to accommodate wiring.

What They Eat

Carpenter ants feed on dead insects, juices of fruits, plant sap, and a variety of household foodstuffs.

Physical Characteristics / Threat Level

Resembling bumble bees, carpenter bees are large, fat bees with fuzzy hairs. Female carpenter bees can sting, but rarely do. Male carpenter bees cannot sting. Carpenter bees are mostly harmless to humans but can cause severe damage to wood structures over a period of years.

Where They Live

Adult carpenter bees live in nests they build inside trees or wooden structures. Adult carpenter bees drill into roundwood at right angles to the grain of the wood. After drilling to a one inch depth, they turn 90 degrees and drill with the grain. In the spring, the long gallery drilled by the female bee is then subdivided into chambers. An egg plus a mixture of pollen and nectar is placed in each chamber. Bee larvae feed on the pollen and nectar. Adult bees emerge in late summer, then overwinter in the wood until the following spring.

What They Eat

Bees feed on the nectar they obtain from flowers. Most of their time is spent traveling between their nest and the flowers where they obtain their food.

Habitat

House mice live in and around homes, farms, commercial establishments and in open fields and agricultural lands. The onset of cold weather each fall in temperate regions causes mice to move into structures in search of shelter and food.

Food Habits

House mice eat many types of food, but prefer seeds and grain. They are considered "nibblers," sampling many kinds of food that exist in their environment. Foods high in fat, protein, or sugar may be preferred even when grain and seed are present including bacon, chocolate candies, butter, and nutmeats. House mice can survive with little or no free water since they obtain their water from the food they eat. However an absence of liquid water or food of adequate moisture content in the environment may reduce their breeding potential.

Reproduction / Behavior

House mice are mainly nocturnal, but considerable daytime activity may be seen in some locations. Mice have poor eyesight, relying on their hearing and excellent senses of smell, taste, and touch. Litters of 5 or 6 young are born 19 to 21 days after mating. Mice are born hairless and with their eyes closed. They grow rapidly and within 2 weeks are covered with hair with their eyes and ears open. Baby mice begin eating solid food at 3 weeks and are sexually mature at 6 to 10 weeks of age. Mice may breed year-round, but when living outdoors, they breed mostly in the spring and fall. A female can have 5 to 10 litters per year.

Habitat

Norway rats live in close association with people. In urban or suburban areas they live in and around residences, in cellars, warehouses, stores, slaughterhouses, docks, and in sewers. On farms they may inhabit barns, granaries, livestock buildings, silos, and kennels. Although they can climb, Norway rates tend to inhabit the lower floors of multistory buildings.

Food Habits

Norway rates will eat nearly any type of food. When given a choice, they select a nutritionally balanced diet, choosing fresh, wholesome items over stale or contaminated foods. They prefer cereal grains, meats and fish, nuts, and some types of fruit. Rats require 1/2 to 1 ounce of water daily when feeding on dry foods, but need less when moist foods are available. Food items in household garbage offer a fairly balanced diet and also satisfy their moisture needs.

Reproduction / Behavior

Norway rats are primarily nocturnal. They usually become active around dusk, when they begin to seek food and water. Some individuals may be active during daylight hours when rat populations are high. Rats have poor eyesight, relying more on their hearing and excellent sense of smell, taste, and touch. Rats use their keen sense of smell to locate food items and to recognize other rats. Their sense of taste is excellent and they can detect contaminants in food at levels as low as .5 parts per million. Litters of 6 to 12 young are born 21 to 23 days after conception. Newborn rats are hairless and their eyes are closed, but they grow rapidly. Young rats can eat solid food at 2 1/2 to 3 weeks of age. They become completely independent at about 3 to 4 weeks and reach reproductive maturity at 3 months of age. Females may come into heat every 4 or 5 days and may mate within a day or two after a litter is born. Breeding often peaks in spring and fall, with reproductive activity declining during the heat of summer and often stopping completely in winter, depending on habitat. The average female rat has 4 to 6 litters per year and may successfully wean 20 or more offspring annually.