The Brown Rat (Rattus Norvegicus) is also known as the Common, Norway or Sewer Rat. The Brown Rat is brownish grey in colour with grey belly fur. Adult rats normally grow to between 20 and 27cm in length, with their tail length adding an additional 16 to 21 cm. The Brown Rat has a blunt shaped nose and is large and thickset in build, with adults normally weighing between 200 and 500g. In towns and cities, they will feed on a wide variety of foodstuffs, e.g. fast food or other foodstuffs dropped by the unwitting public. However, they do have a preference for cereal grains, such as wheat, barley and oats. The droppings of Brown Rats are sausage shaped, 1-2cm in length and are generally found in one part of their living area, which is known as the latrine. Each rat will produce up to 40 droppings per day. Brown Rats need to have a water source to survive and will drink between 20 and 50ml daily. They will have a litter size of 6 to12 young, with a gestation period of 21- 25 days. Each adult female will produce 3 to 6 litters per year, which can lead to a large population arising in a short period of time.
Rats carry a variety of diseases, such as Weil’s disease, Hanta virus and Trichinosis. They also carry disease causing bacteria on their bodies and in their gut, which they transfer to foodstuffs, food preparation areas and free standing water. They also cause physical contamination through hair and droppings deposited in or on foodstuffs. Rats also cause building damage by gnawing through a variety of building structural materials, including pipes and electrical cables, which can cause flooding and fires. Proprietors of buildings and food producing establishments have a legal obligation to rid their premises of rodent infestation. Other reasons for control include loss of reputation and goodwill, fear and financial loss.