In Helpful Tips

According to the National Pest Management Association, 29 percent of Americans have had a rodent problem in their home.  With 45 percent of these problems occurring in the fall and winter, now is the time to learn the signs that you may have an infestation on your hands.


Given that mice can produce 50+ droppings a day, the presence of rodent feces is often the most apparent sign that you have a guest in your home. They are most likely to be found near food, like in cupboards or under sinks, or in hidden areas, such as near nests.

Fresh droppings are dark and moist. Older droppings will crumble easily as they are touched and are more gray in color.  Knowing the difference can help you determine if you have current roommates or if they’ve already moved out.

Droppings can also help you determine the exact type of critter you’re dealing with. Mouse droppings are pointed on both ends and are smaller than rat droppings – less than a quarter inch in size.  Rat droppings are much larger.

More than one size of dropping may show that both juvenile and adult rodents are present, which can indicate the size of the infestation.

Gnaw / Chew Marks

The word rodent comes from the Latin Rodere, “to gnaw” and refers to those mammals characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. This means that they chew constantly and on almost any type of material – even plastic and lead pipes.

Newer gnaw marks will be lighter in color, becoming darker as they age. Marks can also help answer the rat vs. mouse question – mice leave smaller marks behind than rats.

Rub Marks and Runways

In addition to gnaw marks, you may also find rub marks, left by the oil on the rodents’ skin. These can be common along runways such as along interior walls, foundations, pipes, electrical wires and conduits.  If you’re unsure, try shining a flashlight at an angle toward the suspected area.  Or, you can also leave a fine layer of powder – such as flour or baby powder – and see if it is disturbed.


Rodents tend to nest in dark areas where they are unlikely to be disturbed. They build nests from whatever they can find – shredded paper, plant material, fabric, wall insulation, etc.  You may notice this in your yard as well, as rats and mice are attracted to piles of trash, compost, etc. for both food and nesting.

Pet Behavior

The four-legged friend you actually invited into your home might be one of the best indicators if you have a rat or mouse issue. Pets can often smell the musty odor of rodents and their urine, so pay attention if Fido suddenly becomes interested in spaces beneath appliances or low furniture or another new area.  They may also hear rodents better than you, such as rustling or scratching in the walls – especially at night.

Visual Confirmation

Seeing a rat or mouse in your home is definite proof that you have a rat or mouse in your home. While this may seem obvious, it can indicate that you have a more serious problem.  If you only see them at night, the population is probably manageable with traps and bait.  However, daytime sightings can indicate a larger problem that may require professional services.