House mice live inside homes, buildings, and outdoors (where they are referred to as “field mice”). They prefer to nest in dark, secluded areas and often build nests out of paper products, cotton, packing materials, scraps of wall insulation and fabrics.

House mice can cause serious property damage by eating and contaminating food, chewing on personal items, and they are known to start electrical fires by gnawing on wires inside homes and cars.

The Norway Rat is also called the street or sewer rat, and is believed to be of Asian origin, brought to the U.S. on ships from other countries in the 1700s. Norway rats have fairly poor vision and are colorblind. Despite these deficiencies, their hearing, smell, touch and taste are highly developed. They are not extremely agile, but capable of running, climbing, jumping, and swimming.

The Norway rat has brown fur with black hairs mixed in, and they sometimes look dark gray depending on the filth they are exposed to, and/or the location of their nest. Their bellies are usually a lighter color, from gray to off-white and yellowish blends. Norway rats have small eyes and ears, and their tails are shorter than their body length.

Norway rats are social pests that live in underground burrows and they often build their nests close to other Norway’s. This means that where there is one burrow, there are likely others close by. Norway rat burrows have at least one entrance hole and at least one emergency exit, or bolt-hole, which is usually hidden under grass, debris or other things.

Outdoors, Norway rats typically live in fields, farmlands and man-made structures. They often burrow in soil near riverbanks, under piles garbage and woodpiles, under concrete slabs, and along railroad embankments and streams.

Inside homes, Norway rats typically enter in the fall when food and water becomes scarce outside. Norway’s can fit through a hole the size of a quarter, and once inside a home, they often nest in basements, piles of debris or undisturbed items. However, they will also nest on floors above basements and they love sewers. Although rare, Norway rats may also nest in attics.

Norway rats are nocturnal, instinctually foraging for food at dusk, and before dawn. They have hearty appetites, eating several times each night, and again during the daytime. Norway’s carry the food they find to quiet places to eat or to stockpile. Norway rats will eat practically anything, but they prefer meat, fish, cereals, and they love dog food! However, they are picky eaters and creatures of habit. If they eat something they don’t like, Norway rats will quickly develop an aversion to it, and search for another option. Once they find a favorable food source, Norway rats will return time and again.

Norway rats have front teeth (incisors) that continuously grow, so they need to keep wearing them down by gnawing on (and through) almost anything, including plastic and lead pipes, concrete, and wood. Norway’s typically use the same vertical pathway they felt out with their long whiskers to travel between their nest and sources of food and water. In fields and other rural areas, Norway’s usually travel about 100 to 150 feet away from their nest for food and water, but their range is smaller in urban areas, where they only need to venture out about 25 to 100 feet away from their home.

Due to their propensity to gnaw through almost anything, Norway rats can cause serious damage to landscapes, structures, equipment, and personal items, hence making them a costly threat. On the health side, the accumulation of dried rat feces can contaminate food sources, trigger allergic reactions in humans, and spread harmful bacteria, diseases and viruses like Bubonic Plague, jaundice, rat-bite fever, cowpox virus, trichinosis and salmonellosis. Norway rats can also introduce fleas into a home, which can lead to painful, itchy bites, and other health risks.