Roof Rat and Sewer Rat


Rats are a worldwide pest due to their capacity to cause structural damage, to spread life-threatening diseases, and to compete with man for food.

The species most commonly found in Europe is known as the Norway Rat (Rattus norvegicus). A less commonly found species, the Black or Roof Rat, (Rattus rattus), is largely restricted to port areas.

Rats live alongside man, invading his buildings and eating his food. Rats transmit diseases which are potentially fatal to man such as Weil's disease and murine typhus. They also carry organisms which can damage man's health such as Salmonella bacteria, viruses and parasites such as nematodes and worms.

Damage by rats to the fabric of buildings can be costly. Fires can easily be started after a rat has gnawed a cable. Gas and water pipes are also at risk and rat burrowing can undermine foundations and damage water courses.

Physically very strong, rats have been known to survive for two days in open water, to swim a mile in open sea and to get through a gap of less than 25mm.



Rattus Norvegicus

Common Names: Norway rat; Common rat; Brown rat; Wharf rat; Sewer rat

Adult Weight: 300 grams

Length (head + body): 200-250 mm

Length (tail): 150-200mm, shorter than head and body.

Fur, colour: Harsh and shaggy, brown and black on upper head and body grey or off-white underneath.

Ears, hearing: Thick, opaque, short with fine hairs excellent sense of hearing.

Eyes, sight: Small, poor sight, colour blind.

Snout, smell and taste: Blunt, Excellent sense of smell and taste.

Droppings: In groups, but sometimes scattered. Ellipsoidal capsule shaped, about 20mm long.

Habits, habitat: Lives outdoors, indoors and in sewers, nests in burrows, they can climb though not agile, very good swimmer, conservative and somewhat predictable in habit, will avoid unfamiliar objects, e.g. bait trays, and about range 50 metres per day.

Feeding habits: Omnivorous, more likely to eat meat than Rattus Rattus. Consumes up to 30 grams per day, drinks water or eats food with high water content.

Life cycle: Span: 9-18 months.

Sexual maturity: 2-3 months.

Litter size: 8-10 offspring.

Maximum reproduction rate: 7 litters per year.



Rattus Rattus

Common Names: Ship rat; Black rat; House rat; Roof rat.

Adult Weight: 200 grams

Length (head + body): 150-220mm

Length (tail): 180-250mm, usually longer than head and body.

Fur, colour: Smoother and softer than Rattus norvegicus. Usually black or grey

Ears, hearing: Thin, translucent, large and hairless, excellent sense of hearing.

Eyes, sight: Large and prominent, poor sight, colour blind.

Snout, smell and taste: Pointed, Excellent sense of smell and taste.

Droppings: Scattered, Spindle or banana-shaped, about 12mm long.

Habits, habitat: Non-burrowing, Nests mainly in walls, attics, vines and trees Active agile climber, rarely found in sewers. Rather more erratic and unpredictable in habit than Rattus norvegicus, less wary of new objects than Rattus norvegicus and range about 30 metres.

Feeding habits: Omnivorous, mainly fruits, nuts, grains and vegetables. Consumes 25-30 grams per day, drinks water or eats food with high water content.

Life cycle: Span: 9-12 months.

Sexual maturity: 2-3 months.

Litter size: 6-10 offspring.

Maximum reproduction rate: 6 litters per year.