Mice and rats are very hard to control if there is a food and water source for them. The first step is to eliminate water and any form of food that is exposed, even crumbs. Thorough cleaning is important. Next eliminate the access. Stop up all holes, cracks and crevices where the rodents would have entry into the house, office or whatever. Repellents can now work. Try fox urine, hot pepper dusts and sprays. Live traps sometimes have to be used, but the best control is still - cats!
A blackish (or brownish), medium-sized, slender rat with long, naked, scaly tail; tail usually longer than head and body but not always so. External measurements average: total length, 14 inches; tail, 7.5 inches; hind foot, 1.4 inches. Weight, up to 3/4 lb.
Roof rats live in close association with man. They seldom become established as feral animals as do the Norway rats.
They inhabit grocery and drug stores, warehouses, feed stores, and poultry houses and are very common in cotton gins and associated grain warehouses. They may live near the ground, but usually they frequent the attics, rafters, and crossbeams of the buildings. They make typical runways along pipes, beams or wires, up and down the studding, or along the horizontal ceiling joists, often leaving a dark-colored layer of grease and dirt to mark their travel ways.
Like the Norway rat, the roof rat is largely nocturnal and only where populations are relatively high does one see them frequently in the daytime.
They feed on a wide variety of food items, including grains, meats, and almost any item that has nutritional value.
Roof rats breed throughout the year, with two peaks of production - in February and March and again in May and June. The period of least activity is in July and August. The gestation period is approximately 21 days, and the number of young per litter averages almost seven. They mature rather rapidly, are weaned when about 3 weeks old, and are able to reproduce when approximately 3 months old.
The roof rat is destructive to property and foodstuffs. Also, it plays an important part in the transmission of such human diseases as endemic typhus, rat bite fever, and bubonic plague.