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  5. Norway Rat (Ratus Norvegicus)

Norway Rat (Ratus Norvegicus)

Where do they live?

 The Norway rat, also known as the brown or sewer rat, is the largest domestic rodent.

How do they live?

They are burrowers and live in areas where there is clutter and garbage. Norway rats can gain entry to structures by gnawing, climbing, jumping, or swimming through sewers and entering through toilets or broken drains.

Their burrows are found along building foundations, beneath rubbish or walkways, and in moist areas in and around gardens and fields. They are active mostly at night. However, when populations and competition for food are high they will be seen during the day. They have poor eyesight, but they make up for this with their keen senses of hearing, smell, taste, and touch.

How do they live?

On average, it takes about 2 to 3 months for this rat to reach sexual maturity. The average female Norway rat has 4 to 6 litters per year, with 8 to 9 pups per litter. Their life span is about 12 months.

These rats eat a wide variety of foods but prefer cereal grains, meats, fish, nuts, and some fruits. 

How do they affect us?

Rats eat and contaminate foodstuffs and animal feed. They also damage containers and packaging materials in which foods and feed are stored. They cause problems by gnawing on electrical wires and wooden structures such as doors, ledges, corners, and wall material, and they tear up insulation in walls and ceilings for nesting. They also damage garden crops and ornamental plantings.

Some of the diseases that the rats can transmit to humans and livestock are murine typhus, leptospirosis, salmonellosis (food poisoning), LCM and rat bite fever.

How do we control them?

Good housekeeping in and around buildings will reduce available shelter and food sources for Norway rats. Pipes, lumber, crates, boxes, gardening equipment, and other household goods should be stored off-the-ground. Garbage, trash, and garden debris should be collected frequently, and all garbage receptacles should have tight-fitting covers.

Rats can squeeze beneath a door with only a ½-inch (12.7mm) gap. So, cracks and openings in building foundations and any openings for water pipes, electric wires, sewer pipes, drain spouts, and vents should be sealed. Doors, windows, and screens should fit tightly. Their edges can be covered with sheet metal if gnawing is a problem. Coarse steel wool, wire screen, and lightweight sheet metal are excellent materials for plugging gaps and holes.

All exterior doors should be tight fitting and weatherproofed at the bottom.