The Norway Rat (aka: Brown, Sewer, Common, House, or Wharf Rat) is one of the largest rodents to infest houses in Western Washington. They are easily identified by their roundish bodies, small ears, snub muzzle, and a broad tail that is no longer than its body. Norway Rats can be as long as 18 inches from tail to nose, and can weigh up to 1 pound. They tend to spend most of their time near the ground-floor of structures, and they are excellent diggers.
Roof Rats (aka: Black, Ship, Tree, or Climbing Rats) can often be seen walking along power lines or fence tops. They are easily identified by their sleek bodies, overdeveloped ears, and a tail longer than its body. They have a very strong sense of hearing, touch, taste, and smell, and are extremely capable climbers and jumpers, similar in ability to a squirrel. Their only weakness is their eyesight; because of this, Roof Rats are usually nocturnal, preferring to travel and nest in well-covered areas.
For Norway and Roof Rats, burrowing under foundations or chewing through vent screens are some of the most common paths of entry into a house. Rats love nesting in the insulation of a house, in the crawlspace, basement, or attic. Once they find a nest site, rats will begin reproducing, and one female rat can produce approximately 35 pups in her one-year lifespan. Each of those pups is sexually mature within three months, which can create a very large population in a very short period of time.
Feeding preferences of rats closely mirror that of humans, which is why rats will flourish almost anywhere humans can. Therefore, our homes and businesses can potentially provide them with all the food and shelter they need! Rats need little water to survive, and even less when moist foods are available. Even if food and water are not available nearby, they are able to travel over 300ft from their nest each night in search of it.
Rats are neophobic by nature, usually avoiding new items placed in their environment until the items have been there for a while. Rats also have the ability to fit through very small openings, due to their collapsible skeletons. This allows an adult rat to fit through an opening the size of a quarter. When implementing a control strategy, we consider all of these factors.