The Norway Rat is the largest and most common rat in temperate regions of the world like the Pacific Northwest.
Nesting HabitsNorway Rats often burrow in the ground, or live in the lower levels of buildings. They can squeeze through a half inch gap, making rodent exclusion a critial part of effective control. If a hole is too small to crawl through, they will knaw at the edges until the hole is big enough.
Rapid ReproductionFemales produce 3-6 litters a year, each average 7-8 young. One rat can have more than 42 mouths to feed every year, so food supply is very important.