Roof Rat

Structure, Appearance and Characteristics

  • Adult: Weight approx 260 g
  • Body Shape: Slender
  • Nose: Pointed
  • Fur: Fine, coloured grey, black or brown – can be white underneath
  • Ears: Large, prominent, almost hairless
  • Tail: Longer than body and head – uniform colour
  • Droppings: Pointed, 12mm long
  • Good climbers, jumpers, poor swimmer

Life Cycle

  • Rodents are mammals
  • Gestation Period: 23 days
  • Sexual Maturity: 3-4 months
  • Number of Litters per year: 4-5
  • Average number per litter: 6-8
  • Average Lifespan: approx 1 year.
  • Based on figures, one breeding pair can be responsible for producing up to 1000 offspring in a year.

Habitat

More restricted to city life. Mostly found indoors in roof voids. Likely nesting sites include wall and roof voids, but can often move freely throughout the entire building. Outdoors they can nest in vines and trees but seldom burrow. Commonly infest ships and seaports.

Food

  • Omnivorous. Favours nuts, grains, fruits, cereals. (approx 15-22 grams per day)
  • Water intake (15-22 millilitres per day).
  • Need for free water reduces if food has high moisture content.
  • Take larger meals less frequently Foraging Range: 40-50 metres

Pest Status

Major pest. Gnawing, nibbling and contamination of food products through droppings and urine. Transmits numerous diseases. Physical gnawing of wires can cause short-circuits, breakdowns and fires.

Control

Control for rodents comprises four main approaches:

  1. Sanitation – reducing the food and shelter available for rodent activity
  2. Rodent-proofing – alter the building structurally so that rodents cannot gain entry.
  3. Trapping – using traps to physically capture rodents
  4. Chemical Control – covers a wide variety of techniques including baiting, use of tracking powders and gels and in some cases, fumigants.