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Some Common Signs of Rodent Infestation

Do you think you have rodents infesting your home, barn or workplace, but aren't sure?  Here are some common signs that you may have a rodent problem.

bulletYou see rodent droppings. This is one of the most reliable signs that you have a rodent problem.   You may find droppings in places where you store your food or your pet/animal food, such as in cupboards and drawers or in bins.  Because mice like to run in places that offer them some protection from predators, you may find droppings in cupboards or under the sink, along walls, or on top of wall studs or beams.  Mice will leave droppings near their nests as well (see below).  Storage rooms, sheds, barns, or cabins loaded with boxes, bags, old furniture, and other objects make an ideal home for rodents, so you may find droppings there, even inside boxes and other containers.

Deer mice droppings in drawer (3225 bytes)



Workplaces can also make good rodent homes.  Warehouses, restaurants, and the like are obvious places to look because food may be plentiful there.  However, rodents can infest office buildings, too.  Once again, look for droppings in protected places like closets, storage rooms, or inside boxes.

Want to know what droppings look like?  See the bottom of this page!

Deer mouse nesting in old chair (4450 bytes)

large view (Click on image to view as pop-up window)

bulletYou see signs of rodent nests.  Rodents tend to build their nests from materials that are soft, fuzzy, or warm.  Among common rodent nest materials are shredded paper, bunches of dry grass or small twigs, fabric, and furniture stuffing.  Rodents will nest wherever safety from enemies can be found close enough to food and water, and they prefer places that are relatively quiet.  Inside buildings, here are some places to look: bulletinside cabinets bulletunder or inside dressers bulletin and among boxes bulletbehind and inside machinery and appliances (kitchen appliances such as stoves or refrigerator drip pans; water coolers; and electric motor cases or computer cases) bulletinside upholstered furniture bulletinside double walls or the space between floors and ceilings.bulletYou find food boxes, containers, or food itself that appears to be nibbled.  Look for droppings nearby.  Rodents can chew through plastic, so plastic bags do not make safe food storage containers.bulletYou find signs of  rodent "feeding stations."  These are semi-hidden spots where rodents eat food they have collected.  At these stations, rodents may leave larger-than-normal amounts of droppings/urine, plus remnants of a variety of foods (such as nut shells), bits of plastic or paper, and cockroach carcasses.bulletYou find evidence of gnawing.  To get to food, rodents will gnaw on almost anything that is softer than the enamel of their teeth.  This includes such things as wood, paper board, cloth sacks, and materials even harder than these.  Because rodents' teeth grow continuously, they must gnaw to keep them short.  That may help to explain why chair legs or similar surfaces show gnawed spots or tooth marks in rodent-infested places.bulletYou notice an odd, stale smell.  In closed-up rooms infested by rodents, you will commonly smell an unusual, musky odor.bulletYou see a mouse in your house.  However, this doesn't happen very frequently!   Why?  Rodents are normally active at night, and generally avoid humans.   If you have rodents, unless the infestation is large, you may never see one.

Remember that not all types of rodents carry hantavirus. Neither common house mice nor common rats have been associated with HPS in humans, for example.  Yet because it can be tough to tell just what kind of rodents you have, play it safe -- clean up the infestation and rodent-proof your home or workplace.

Read our Meet the Rodents page to learn how to identify the rodent species that carry hantavirus in North America.

Size of Deer Mouse and White-footed Mouse Droppings Compared with the Droppings of Other Household Pests:  Close to Actual Size

Size of droppings of deer mouse and white footed mouse compared to that of other common pests

The image above may not print at actual size.  However, you can download a .tif file of the same image.  When printed, the "1 inch" line should actually measure one inch long.
Download the 300 dpi .tif version (459 Kb)
Download the 150 dpi .tif version (1.9 Mb)

Related topics


Facts about Hantavirusbullet

Ready to clean up a rodent infestation?  Visit "Tips for Preventing Hantavirus: Cleaning Up Rodent-Infested Areas" to learn how to do so safely.bullet

Looking for more details on identifying a rodent infestation?   Rodent-Proofing Techniques.