The Norway rat is larger and more aggressive than the Roof Rat.
Norway Rats Appearance:
As an adult, the Norway Rat can weigh between 12-16 oz. with a body length of 6-8 inches long. The nose is blunt with small ears, and small eyes. The fur is shaggy and coarse with variation in colors. The tail is shorter than the head and body combined, and scaly.
Norway Rats Inspection
The Norway Rat droppings are 1/4 to 1/2 inch in length. The droppings are capsule shaped and have blunt ends. Their droppings are usually a shiny black but may vary according to their diets.
Norway Rats and Roof Rats will leave a hind foot track of about 3/4-1 inch where a mouse's track measure's 3/8 of an inch or less.
Norway Rats will leave a mark as they drag their tails between their feet. Using unscented baby powder or flour can be dusted in areas of suspect. Lightly use the powder in these areas.
Norway Rats can leave gnarled hole about 2 inches in diameter. The holes have rough edges. Their preference is to gnaw on wood, but will gnaw on electrical wiring causing damage.
Rat burrows can be found along foundations, or beneath rubbish and shrubbery. If the burrow is active it usually clear of vegetation. Rat runways are smooth and well packed. Indoors, these runways are free of dust and dirt.
Norway Rats Diet:
Norway Rats will eat a lot of types of food but prefer proteins and carbohydrates. Unlike mice, they need water for survival.
Norway Rats Habits and Biology:
The young Norway Rats reach sexual maturity in 2-3 months. Females average 4-7litters a year, with 8-12 pups per litter. Adults live about a year and prefer to live in colonies.
The Norway rat generally prefers to live in underground tunnels or burrows.
They can be found near food sources such as barns, granaries, silos, and livestock if found on farms.
If found in urban areas, they can be found in the ground in yards or any available ground space. In most cases, they will be found in underground tunnels but may also live inside buildings their whole lives.
The Norway Rats can enter homes during the night, seeking food, then return to burrows.
Norway Rats need a water source. They will seek out water in sinks, toilets, pet dishes, moisture from utility pipes and rain puddles.
Their nesting burrows on the outside are often along the foundation of walls. As the rat family grows, more burrows are built, resulting in a network of underground tunnels.
If found inside, Norway Rats usually are found nesting in crawl spaces and basements, but may be found in attics and celling areas if the population is large.
The Norway Rat's nest may be built from soft material such as paper or grass. If necessary, the Norway Rat will climb a structure to enter a building. The Norway Rat is also an excellent swimmer.
As with other rats, Norway Rat are suspicious of changes in the environment. This makes baiting or trapping a little tricky. It may take a few days of undisturbed bait or traps to be trusted enough for them to approach them.
Expect Norway Rat activity during the night. Their peak times are either just before dawn or at dusk. If their population is so large or if they are disturbed, you can detect activity during the day.