The Norway rat, also known as the ( water rat, sewer rat, wharf rat, barn rat, house rat, and gray rat ) was transported  to  North America  in the late 1700’s by settlers who traveled by ship from Europe. The Norway rat is now the most common rat found throughout the United States. The adult rat weighs 10 to 17 ounces, is 7 to 10 inches long , and has a course gray, grayish brown, or black coat with a yellow-white underside.  The ears are small and close to the body. The rat is color blind and has poor eyesight which is why they see only light, shadows and movement. The nose is blunt although rats have a very good sense of smell. The name rodent comes from the greek word rodentsha-to gnaw. Rats can gnaw through wood, uncured concrete, lead, aluminum, copper, and PVC pipe.  The tail is 6 to 8.5 inches long  and is darker on top then the bottom. The droppings of the Norway rat are about ¾ inch and blunt on both ends. Each rat averages 30 to 180 droppings per day.

     The Norway and Roof Rat are sexually mature and capable of mating at 3 months old. Rats can be pregnant and still feed their young at the same time. The gestation period is 21 to 23 days, and the female averages 3 to 7 litters per year ( Norway rats, 6 to 12 pups and Roof rats, 5 to 8 pups per year). Weaning lasts  28 to 35 days. After giving birth rats are capable of being in heat again in 24 to 48 hours. Rats can live for up to 18 months.

Habitat 

     Norway rats have a very strong social hierarchy. The largest and strongest rats (alpha) get the best food and harborage. The weaker and younger rats (omega) must eat after the alpha rats and eventually get pushed out to find food elsewhere. Rats consume ¾ to 1 ounce of food, and ½ to 1 ounce of water per day. Peak feeding times are ½ hour after sunset and ½ hour before sunrise.   Norway rats like to borrow in soil and are excellent swimmers and climbers. Territories of rats are from 50 to 150 feet from nesting area but will travel up to 300 feet if needed. Rats are omnivores and will feed on grain products, dog food, meats, vegetables, and fruit. These foods are found in garbage cans, dumpsters, and at worse case, your kitchen. 

Inspection

    When inspecting for rodent infestation some things to look for are borrows, droppings, grease rub marks, gnaw marks, tracks, runways, odors, and urine stains. A thorough inspection around and under all shrubbery and ground covering , cement slabs, wood piles, stone walls, fences,under dog houses, sheds, and compost piles will let you know the extent of the infestation.  Sewer line brakes can also create access for rodents. Rats have been known to gain access to homes by crawling up sewer lines and entering by way of basement toilet.

Sanitation

     Eliminating the food source of rodents is the first step to elimination. Keeping garbage cans covered securely and dumpster lids closed and emptied frequently is very crucial. Rats will hoard dog food if left out on a regular basis.  Feeding birds is nice but spillage will attract rodents.

Structual

     Stopping rodents from entering a home or building is much easier then eliminating them once they are in. Make sure all doors are weather-stripped properly. Inspect foundation for cracks and voids, especially field stone foundations.  Seal all openings around plumbing, cables, and electrical wiring from air conditioning units. And last but not least, rodents are excellent climbers so don’t forget to look up.