Denton County Termite
and Pest Control Inc.
Serving North Texas Since 1940
Recognizing Rat Infestations
The presence of rats can be detected by droppings or evidence of fresh
gnawing. Tracks can be seen in mud and on dusty surfaces. Runways and
burrows may be found next to buildings, along fences or railroad tracks, and
under low vegetation and debris.
Rats will eat nearly any type of food, but they prefer high-quality foods such as
meat and fresh grain. Rats require 1/2 to 1 fluid ounce of water daily when
feeding on dry food. Rats have keen taste, hearing and sense of smell. They
will climb to find food or shelter, and they can gain entrance to a building
through any opening larger than 1/2 inch across.
Rats have litters of 6 to 12 young, which are born 21 to 23 days after mating.
Young rats reach reproductive maturity in about three months. Breeding is
most active in spring and fall. The average female has four to six litters per
year. Rats can live for up to 18 months, but most die before they are one year
Rat Prevention and Control
Sanitation. Poor sanitation and the presence of garbage help rats to survive
in residential areas. Good sanitation will effectively limit the number of rats that
can survive in and around the home. This involves good housekeeping, proper
storage and handling of food materials and refuse, and elimination of rodent
shelter (harborage). Outside dog pens must be properly maintained to reduce
potential rat problems. Removing clutter around homes allows inspection for
signs of rats. Good sanitary practices will not eliminate rats under all
conditions, but will make the environment less suitable for them to thrive.
Rat-Proof Construction. The most successful and permanent form of rat
control is to "build them out" by making their access to structures impossible.
Ideally, all places where food is stored, processed or used should be
rodent-proof. Store bulk foods, bird seed and dry pet food in metal cans with
Seal any openings larger than 1/4 inch to exclude both rats and mice.
Openings where utility conduits enter buildings should be sealed tightly with
metal or concrete. Equip floor drains and sewer pipes with tightfitting grates
having 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
Disposal of Dead Rodents
Always wear intact rubber or plastic gloves when removing dead rodents and
when cleaning or disinfecting items contaminated by rodents. Soak or spray
dead rodents with a disinfecting solution (3 tablespoons of bleach per gallon
of water or a commercial disinfectant containing phenol) until thoroughly wet
and place in a plastic bag. The bag should be placed in a second bag and
tightly sealed. Dispose of rodents in trash containers with tightfitting lids. After
handling rodents, resetting traps and cleaning contaminated objects,
thoroughly wash gloved hands in a general household disinfectant or in soap
and water. Then remove gloves and thoroughly wash your hands with soap
The Norway rat (Rattus norvegicus) is a stocky burrowing rodent,
unintentionally introduced to North America by settlers who arrived on ships
from Europe. First introduced into the United States about 1775, this rat has
now spread throughout the contiguous 48 states. The Norway rat is found
generally at lower elevations but may be found wherever humans live. Also
called the brown rat, house rat, barn rat, sewer rat, gray rat, or wharf rat, it is a
slightly larger animal than the roof rat. The nose is blunt, the ears are small,
close set and do not reach the eyes when pulled down. The tail is scaly,
semi-naked and shorter than the head and body combined. When
distinguishing the Norway rat from the Roof rat, pull the tail back over the body.
The tail of the Roof rat will reach the nose. The tail of the Norway rat will not
reach beyond the ears. Adult Norway rats weigh an average of about 1 pound.
Their fur is coarse and usually is brownish or reddish-gray above, and
whitish-gray on the belly. Blackish individuals occur in some locations.
Norway rats live in close association with people. They burrow to make nests
under buildings and other structures, beneath concrete slabs, along stream
banks, around ponds, in garbage dumps, and at other locations where
suitable food, water, and shelter are present. On farms they may inhabit barns,
granaries, livestock buildings, silos, and kennels. In urban or suburban areas
they live in and around residences, in cellars, warehouses, stores,
slaughterhouses, docks, and in sewers. Although they can climb, Norway rats
tend to inhabit the lower floors of multi-story buildings.
Norway rats 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, nut, 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.
General Biology, Reproduction and Behavior:
Norway rats are primarily nocturnal. They usually become active about dusk,
when they begin to seek food and water. Some individuals may be active
during daylight hours when the rat population is high, when disturbed (weather
change, construction, etc.) or when their food source is threatened. The
territories of most rats are between 50 and 150 feet radius of the nest. In
populations where there are many rats and abundant food and shelter, the
territories will be towards the lower end of the range. If need be, however, rats
will travel 300 feet or more daily to obtain their food and water. In urban areas
most rats remain around the buildings and yards which provide their
necessities, and unless they are disturbed, they do not move great distances.
Rats have poor eyesight beyond three or four feet, relying more on their
hearing and their excellent senses of smell, taste and touch. Norway rats are
very sensitive to motion up to 30-50 feet away. They are considered
Rats use their keen sense of smell to locate food items and apparently to
recognize other rats. Norway rats rely on their sense of smell to recognize the
odors of pathways, members of the opposite sex who are ready to mate,
differentiate between members of their own colonies and strangers, and to tell
if a stranger is a strong or weak individual.
Norway rats use hearing to locate objects to within a few inches. This highly
developed sense (combined with their touch sensitivity) can pinpoint someone
rolling over in bed to a six inch area. The frequency range of their hearing (50
kilohertz or more) is much higher than that of humans (about 20 kilohertz.)
Norway rats have a highly developed sense of touch due to very sensitive
body hairs and whiskers which they use to explore their environment. Much of
a rodentís movement in a familiar area relies heavily on the senses of touch
and smell to direct it through time-tested movements learned by exploration
and knowledge of its home range. Rodents prefer a stationary object on at
least one side of them as they travel and thus commonly move along walls, a
fact which is very useful when designing a control program.
Their sense of taste is excellent, and they can detect some contaminants in
their food at levels as low as 0.5 parts per million. This highly developed taste
sensitivity may lead to bait rejection if the rodent baits are contaminated with
insecticide odors or other chemicals.
Norway rats usually construct nests in below-ground burrows or at ground
level. Nests may be lined with shredded paper, cloth, or other fibrous material.
Litters of 6 to 12 young are born 21 to 23 days after conception. Newborn rats
are naked and their eyes are closed, but they grow rapidly. They can eat solid
food at 2 1/2 to 3 weeks. They become completely independent at about 3 to
4 weeks and reach reproductive maturity at 3 months of age, sometimes as
early as 8 weeks.
Female Norway rats may come into heat every 4 or 5 days, and they may
mate within a day after a litter is born. The average female rat has 4 to 6 litters
per year and may successfully wean 20 or more offspring annually.
When eliminating Norway rats, remember that glue boards are not very
effective on large rodents. Snap traps and live traps will work. The most
effective control method for these rats is the use of weather proof bait boxes.
Please contact us for a rodent elimination service.
The roof rat (Rattus Rattus) is one of two introduced rats found in the
contiguous 48 states. The Norway rat is the other species and is better
known because of its widespread distribution. When distinguishing the
Norway rat from the Roof rat, pull the tail back over the body. The tail of the
Roof rat will reach the nose. The tail of the Norway rat will not reach beyond
the ears. A third rat species, the Polynesian rat, is present in the Hawaiian
Islands but not on the mainland. Rattus Rattus is commonly known as the roof
rat, black rat or ship rat. Roof rats were common on early sailing ships and
apparently arrived in this country by that route. This rat has a long record as a
carrier of plague.
Roof rats range along the lower half of the East Coast and throughout the
Gulf States and upward into Arkansas. They also exist along the Pacific
Coast and are found on the Hawaiian Islands. The roof rat is apparently not
quite as adaptable as the Norway rat, which is one reason it has not spread
throughout the country. Its geographic distribution suggests it is more suited
to tropical and semi-tropical climates. Occasionally isolated populations are
reported from areas not within their normal distribution range; however, these
instances are rare. Most of the Great Plains states are free of roof rats but
infestations can occur.
Roof rats are more aerial than Norway rats in their habitat selection and often
will live in trees or on vine covered fences. Landscaped residential or
industrial areas provide good habitat, as does vegetation of riverbanks and
streams. They will often move into sugarcane and citrus groves. Roof rats are
sometimes found living in or around poultry or other farm buildings as well as
in industrial sites where food and shelter are available. Being agile climbers,
Roof rats frequently enter buildings from the roof or accesses near utility lines
which they use to travel from area to area. They have been found in sewer
systems, but this is not very common.
The food habits of roof rats resemble those of tree squirrels, since they both
like a wide variety of fruit and nuts. They also feed on a variety of ornamental
and native plant materials. Like the Norway rat, they are omnivorous and will
feed on most anything if necessary. Roof rats usually require water daily,
though their local diet may provide an adequate amount if high in water
Reproduction and Development:
Born in a nest about 21 to 23 days after conception, the young rats are
naked and their eyes are closed. The 5 to 8 young in the litter develop
rapidly, growing hair within a week. When they are 9 to 14 days old, their
eyes open and they begin to explore for food and move about near their nest.
In the third week they begin to take solid food. The number of litters depends
on the area and varies with nearness to the limit of their climatic range,
availability of nutritious food, density of the local rat population and age of the
rat. The young may continue to nurse until 4 or 5 weeks old. Young rats
generally cannot be trapped until about 1 month old. At about 3 months of
age they are completely independent of the mother and are reproductively
mature. In tropical or semitropical regions, the breeding season may be
nearly year-round. Usually the peaks in breeding occur in the spring and fall.
Roof rats usually begin searching for food shortly after sunset. If the food is in
an exposed area and too large to be eaten quickly, yet not too large to be
moved, they will usually carry it to a hiding place before eating it. Many rats
will cache or hoard considerable amounts of solid food, which they may or
may not eat later. When necessary, roof rats will travel considerable
distances for food. They can often be seen at night running along overhead
utility lines. They may live in trees or attics and climb down to a food source.
This is important from the standpoint of control, for traditional baiting or
trapping on the ground or floor may intercept very few roof rats. Roof rats
have a strong tendency to avoid new objects in their environment and this
can influence control efforts. These rats may take several days before they
will approach a bait station or trap.
Rats see poorly, relying more on smell, taste, touch and hearing. They are
considered to be colorblind, responding only to the degree of lightness and
darkness of colors. Roof rats also have an excellent sense of balance. They
use their tails for balance while traveling along overhead utility lines and are
very agile climbers.
Please contact us for a rodent elimination service.
Identification and Range:
The house mouse (Mus musculus) is a small, slender rodent that has a
slightly pointed nose; small, black, somewhat protruding eyes; large,
scantily haired ears, and a nearly hairless tail with obvious scale rings. The
adult mouse weighs about 2/5 to 4/5 ounces. They are generally
grayish-brown with a gray or buff belly. Similar mice include the
white-footed mice and jumping mice( which have a white belly), and harvest
mice (which have grooved upper incisor teeth.) Native to central Asia, this
species arrived in North America along with settlers from Europe and other
points of origin. A very adaptable species, the house mouse often lives in
close association with humans and therefore is termed one of the
"commensal" rodents along with Norway and roof rats. Following their
arrival on colonistsí ships, house mice spread across North America and
now are found in every state including coastal areas of Alaska, and in the
southern parts of Canada.
House mice live in and around homes, farms, commercial establishments,
as well as in open fields and agricultural lands. The onset of cold weather
each fall in temperate regions is said to cause mice to move into structures
in search of shelter and food.
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House mice eat many types of food but prefer seeds and grain. They are
not hesitant to sample new foods and are considered "nibblers," sampling
many kinds of items that may exist in their environment. Foods high in fat,
protein, or sugar may be preferred even when grain and seed also are
present. Such items include bacon, chocolate candies, butter and
nutmeats. A single mouse eats only about 3 grams of food per day (8
pounds per year) but because of their habit of nibbling on many foods and
discarding partially eaten items, mice destroy considerably more food than
they consume. Unlike Norway and roof rats, they can get by with little or no
free water, although they readily drink water when it is available. They
obtain their water needs from the food they eat. An absence of liquid water
or food of adequate moisture content in their environment may reduce their
General Biology, Reproduction, and Behavior:
House mice are mainly nocturnal, although at some locations considerable
daytime activity may be seen. Seeing mice during daylight hours does not
necessarily mean there is a high population present, although this usually is
true for rats Mice have poor eyesight, relying more on their hearing and
their excellent senses of smell, taste and touch. They are considered
House mice can dig and may burrow into the ground in fields or around
structures when other shelter is not readily available. Nesting may occur
here or in any sheltered location. Nests are constructed of fibrous materials
and generally have the appearance of a "ball" of material loosely woven
together. These nests are usually 4 to 6 inches in diameter. Litters of 5 or 6
young are born 19 to 21 days after mating, although females that conceive
while still nursing may have a slightly longer gestation period. Newborn
mice are naked and their eyes are closed. They grow rapidly and after 2
w3eeks they are covered with hair and their eyes and ears are open. They
begin to make short excursions from the nest and eat solid food at 3
weeks. Weaning soon follows, and mice are sexually mature as early as 6
to 10 weeks old.
Mice may breed year-round and a female may have 5 to 10 litters per year.
Mouse populations can therefore grow rapidly under good conditions,
although breeding and survival of young slow markedly when population
densities become high.
During its daily activities, a mouse normally travels an area averaging 10 to
30 feet in diameter, seldom traveling further than this to obtain food or
water. Mice constantly explore and learn about their environment,
memorizing the locations of pathways, obstacles, food and water, shelter
and other elements in their domain. They quickly detect new objects in their
environment, but they do not fear novel objects as do rats. This behavior
should be remembered if faced with a large population of mice in a
residential, industrial or agricultural setting. Proper placements of mouse
bait is a must if you are to have a successful baiting program. Please
contact us for a rodent elimination service.
RAT PREVENTION AND CONTROL