|THE HOUSE MOUSE|
|DISTRIBUTION||It is now found throughout the world, from the tropics to the Arctic and Antarctic.|
mice should not be confused with young rats. The mouse's head and feet are
in proportion to its body. House mice are extremely prolific breeders.
At 35 days of age they mature and carry embryos for 18 - 21 days. If a female aborts, she can become pregnant again within 48 hours. The average litter size is about six. Variation in genetics, food supply and temperatures can affect these numbers. A female suckles her young for about four weeks. The female may become pregnant following parturition or while lactating. Therefore if all goes well, a female can have litters approximately every 40 - 50 days. Under optimum conditions (often found indoors) mice can breed through the year. Newborn mice are extremely small, pink and naked. After about three weeks they are fully covered with hair, make short trips from the nest and begin feeding on solid food. Mice usually live for 15 - 18 months.
|RATS : NORWAY RAT - ROOF RAT|
|DISTRIBUTION||The Norway rat is the most common of rats and occurs practically everywhere. The roof rat is found commonly in sea ports and is also a house rat.|
|DESCRIPTION||The males are capable of pairing at all times but the females are receptive
only during heat periods which may extend to nine months. The number of
young in a litter may vary from 6 to 22. The average number in pregnant
females is 6 to 8. There may be from 3 to 12 litters in a single year with
an average of 3 to 6 per annum. Newborn rats depend on their mother for
food for about three weeks and then feed on solid food.
The life of rats in a population is about six months.
and mice have rather poor vision and are colorblind, but the sense of smell,
taste, hearing and touch are keenly developed. They usually become active
half an hour after dusk, after the premises have become quiet. When unmolested,
rats roam about seeking food during any part of the day or night.
One of the favorite nesting places for rats in buildings is the closed space under the building ground floor. All other closed spaces of buildings may be utilized by rats if they can gain access to them. Nests will often be found in piles of rubbish and merchandise if the latter is stored over a month without being moved. In residential areas they live outdoors in yards, garages, sheds and in sewers. They also dig the earth in the tunnels with their front feet and shove the loose soil back under their belly. They can also run, climb, jump and swim.
|POTENTIAL HAZARDS||Rodents similarly infest our structures, destroy and contaminate our food
supply . They are responsible for damage in the home and warehouse.
They gnaw upholstery, bolts of silk, papers, books and like items for
nesting material. They also gnaw hard substances such as bone, aluminum, lead
and similar materials. The tooth enamel has a hardness index of 5,5 times harder
even than steel. And the jaws can exert pressures of 24,000 lbs./inc2. Rats
can readily chew through plastic water pipes, irrigation systems and garbage
cans. Accounts have been made of the rat's ability to start fires by carrying matches to their
hiding places, as well as by causing short circuits through the gnawing of
Disease organisms may be transmitted either directly through the rodent's bite or carried from the rodent to a flea, tick or mite, which bites man and transfers the pathogen, or by contaminating food or water with their dung or urine (plague, murine typhus fever, leptospirosis - trichinosis - food poisoning)
|PREVENTION|| Two principles must be kept in mind in the rat-proofing of buildings:
|CONTROL||A complete rodentification program must be applied for successful elimination. Recognition of runways, nests and burrows is very important. Useful tools such as anticoagulant rodenticide are available. Glue boards, snap traps and ultrasonic devices are available but less effective in heavy infestation.|
|CHARACTERISTICS OF COMMENSAL RODENTS|
|Characteristic||Norway Rat||Roof Rat||House Mouse|
|General appearance||large , robust||sleek ,graceful||small,slender|
|Adult size Weight (gm)||7-18 oz/200 - 500g||5 - 9 oz/150 - 250g||0,4 - 1 oz/12 - 30g|
| Length ( nose to tip of tail )
Head and body ( mm )
|7- 9,5 in/18-25 cm||6 - 8 in/16 - 20 cm||2 - 3,5 in/6 -9 cm|
|Tail ( mm )||6 - 8 in/15 - 21 cm||7 - 10 in/19 - 25 cm||3 - 4 in/7 -10 cm|
|Ears||small,covered with short hair do not reach eyes..||large ,nearly naked can be pulled over eyes||large,some hair|
|Tail||dark above,pale beneath||uniformly dark||uniformly dark|
|Fur|| brown with scattered black ( agouti ) venter grey to yellow/white
| agouti to gray to black venter white gray or black
| Light brown
|Droppigs||capsule shaped, 2cm / 3/4 - 1 in|| spindle shaped,
1 cm / 0,5 in
| rod shaped,
3 – 6 mm / 0,5 in
|Sight||poor,color blind||poor, color blind||poor ,color blind|
|Smell, taste, touch, hearing||excellent||excellent||excellent|