They live on the principle of commensalisms that is sharing the human life without any positive feedback except damages they give in return. They can enter a commercial building through stocks imported/exported, cracks & crevices ,fields their natural habitat, damp areas, trashes, etc. They can adapt any mode of entry to enter a building. They mostly prefer areas where they can find suitable environment of food, shelter, breeding, etc. They can chew anything from papers to electrical wires. They spread diseases like plague, typhus, etc. Types Of Rats Norway Rats Roof Rats House MiceNORWAY RATS The Norway rat is also known as the Brown rat, Gray rat, Common rat, House rat, Wharf rat, Sewer rat, Barn rat and Water rat. They are omnivores-they can eat just about anything, but they prefer meats, fish, flour, cereal grains, fruits and vegetables. They consume 3/4 to 1 ounce of food each day and require water daily to survive, from 1/2 to 1 ounce of water every day. Life Cycle - Norway rats will become sexually mature in 3-5 months of age. The females create a nest in isolated places when inside a building, or in burrows or tunnels when outside. There can be from four to seven litters each year, with up to a dozen young in each litter, so the population can grow quite rapidly. Adults only live from 9-12 months. ROOF RATS Roof Rats are probably the most common rat species found. They are also known as Alexandrian rats, Black rats, Fruit rats and Ship rats. They usually consume 1/2 to 1 ounce of food daily, and drink up to 1 ounce of water daily. A water source is also essential. The Roof rat is notable by its larger ears, pointed nose, a tail that is longer than the body, and an average body weight of 6-12 ounces. Roof rats also have a sharp sense of smell. life Cycle - The female Roof rat reaches sexual maturity at 3 months of age. They are in heat approximately every 4-5 days. The gestation period is 21 to 23 days, with each litter being 5-8 pups. After giving birth the female is capable of being in heat again in 24 to 48 hours, so many generations can be produced each year. HOUSE MICE The House mouse is a small, slender rodent with a slightly pointed nose; small, black, somewhat protruding eyes; large, sparsely haired ears; and a nearly hairless tail with scale rings. House mice will eat many types of food but prefer seeds and grain. Foods high in fat, protein, or sugar may be preferred even when grain and seed are present. Such items include bacon, chocolate candies, butter, and nutmeats. Unlike Norway and Roof rats, House mice can survive with little or no water, obtaining their water from moisture in the food they eat. Life Cycle - 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 after 2 weeks their eyes and ears open and they are covered with hair. They begin to make short excursions from the nest and eat solid food at 3 weeks. Weaning soon follows, and mice are sexually mature at 6 to 10 weeks of age. Mice may breed year-round. The female has 5 to 10 litters per year. Mouse populations can therefore grow very rapidly under ideal conditions.
