Brown Rat(Rattus norvegicus)

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Brown Rat

Brown Rat, Norway Rat or Sewer Rat
(Rattus norvegicus)
Adult : Brown, with whitish brown underside, small ears. Size of Head & body length 20-27cms, with a 15-2 cms tail. Their tails are shorter than their combined head & body length.
Life Cycle:
Prolific breeders with about 60-70 young in a year.   Sexually mature adults can give birth every 24- 28 days.
Brown Rats are commonly found in areas of human habitation or where good harbourage is found close to food sources.They occur both indoors and outdoors and can be abundant in Sewers and Farms. As excellent swimmers, rats will also thrive in watercourse areas or use them as a thoroughfare.


Capable of exploiting any niches offered by man, brown rats can survive in all climatic areas in the UK and can breed throughout the year.


Rats cause damage to structures and property they can cause significant economic harm.


Signs of infestation include the presence of droppings, fresh gnawing, tracks and smear marks.


They also pose a risk to public health as they may transmit diseases such as salmonellosis (food poisoning). More importantly they can carry bacterial leptospires which can cause Leptospirosis or Weil’s Disease in human. This can be passed to humans from rat urine or fresh wet droppings. The leptospires can remain active in water or wet ground and consequently pose a hazard to humans. Once they can penetrate the body via breaks in the skin Weil’s disease can develop resulting in mild-flu like symptoms, kidney and renal failure or death.   Those most at risk are agricultural workers, Sewer Workers, Abattoir and Pest Control Workers.


A relatively high incidence occurs from those in the leisure industry associated with water – such as canoeists or anglers.


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