There are two types of mice that are most likely to invade your Pennsylvania home which can be hard to tell apart. Both of these mice have tiny mouse ears, pointed noses, black beady eyes, and thin tails that are about the same length as their body. But these two mice do not present the same issues.

Common House Mouse (Mus Musculus)

These are mice that prefer to live inside our homes with us. They can infest every nook and wall void with ease. If you have these mice, you aren’t likely to get rid of them. They reproduce quickly and are not inclined to leave once they have established themselves.

Deer Mouse (Peromyscus Maniculatus)

While this mouse species prefers to live outside in holes formed in trees, hollowed out logs, under stones and other natural items, as well as yard clutter, it can be a significant health risk when it establishes itself in attics, crawl spaces, and cellars. The CDC directly connects deer mice with Hantavirus pulmonary syndrome, which is contracted through inhalation of particulate matter in areas of feces contamination. A mask or respirator should be used when going into locations that have been infested by deer mice.


There are two types of rats that make themselves a pest issue in Pennsylvania, and like those mice, these rats can be hard to distinguish from each other. They are both big and stocky, like a rat, with a rounded rat nose, and a thick rat tail. But, the easiest way to tell them apart is by knowing what a Norway rat looks like. They are mostly a brown or reddish brown coloring on top and a pale white coloring on their belly – that is assuming they haven’t been crawling around in a sewage pipe. Roof rats come in a wide variety of species and colors.

Roof Rats (Rattus rattus)

As their name implies, roof rats like to live in high places, such as trees, but they will also invade a structure through vulnerable rooflines, eaves, and soffits. It is important to make sure that tree branches are cut to prevent this rat from gaining access to your roof. These rats can also use downspouts of gutter systems to get up to your roof. Block these off with steel wool.

Norway Rats (Rattus norvegicus)

These rats are ground rats. They prefer to dig burrows under junk piles in your yard, and use low pathways into your home. If you have Norway rats inside, there should also be evidence of them outside. But, it is not uncommon for these rats to live entirely inside a man-made structure, especially if there are large enough food sources like meats, cheeses, and dry dog food.


If you own a home or business in Pennsylvania, there is a good chance you’ve seen a squirrel. These animals don’t have any problem living in close proximity to humans. When they get inside, they contaminate secluded spaces with their feces and urine, and create a considerable racket. All squirrels chew their way in through rooflines, soffits, eaves, and porch overhangs. Exclusion installations and IPM protocols are the only effective defense against these creatures.

Northern Flying Squirrel (Glaucomys sabrinus)

Of all the squirrels that may infest your attic spaces, garage, shed, or outbuildings, this squirrel is distinctly different. While all of the other squirrels on this page are diurnal, flying squirrels are nocturnal in nature.

Other Common Squirrels

Gray squirrel (Sciurus carolinensis), Red squirrel (Tamiasciurus hudsonicus), Fox Squirrel (Sciurus niger) are all diurnal creatures that can invade man-made structures, especially in fall when temperatures start to drop.