Creature feature
Common Rat or Norway, Sewer or Brown Rat - (Rattus norvegicus)
Brown in colour with an off white underbelly, adults up to 500g with a body length 270mm and a tail length of up to 200mm.

Life cycle
Litter size 8 to10 - sexually mature 2-3 months - up to 7 litters per year Lifespan 9-18 months Life Style The common rat is a very adaptable omnivorous creature. It has poor eyesight and is colour blind. The rat compensates for this with an excellent sense of touch, taste, smell hearing. Colonies typically develop from a pair or single pregnant female. Socially structured colonies develop occupying territories that are vigorously defended. Males compete for access to receptive females, dominant males wining the right to copulate. When conditions are favourable (warm temperatures, undisturbed habitat, surplus food and water) populations can develop rapidly. The fact that the female can come into oestrus prior to weaning means that this rapid increase is compounded. The common rat is very athletic, a good swimmer, climber, jumper and burrower.

Pest Factor
Rodent incisors grow continuously hence the habit of gnawing; this has been known to cause deadly fires when electric cables are involved. The common rat is known to carry diseases that affect humans such as Weil's disease (leptospirosis); this has been found in the kidneys of up to 50% of some rat populations. Salmonella infections commonly occur from the contamination of food and water with rodent excreta. The bacterium causing Plague is transmitted to man by the rat flea. Isolated outbreaks still occur. Other rodent-borne diseases include rat-bite fever, lymphocytic choriomeningitis and murine typhus. Parasites transmitted by rodents include ringworm, tapeworms, tick and fleas.