Signs of Rodent Activity

Signs of Rodent Activity

Live rat sightings are a sure sign that an infestation is in progress, but may not occur until an infestation has become severe. To determine whether rodents are present inside or outside a home, look for these signs:

Rub and Grease Marks

Rats will often use the same route of travel to move between their nest and sources of food or water. This is called a ‘runway’. Over time, dirt and oils from their fur will leave a smudge or stain on walls or other surfaces. You may see these rub marks on beams or rafters, on vertical pipes, or along ledges. You may also see swing marks where rats ‘swing’ their bodies under obstacles.


You might see rodent droppings around compost or garbage bins, near pet food bowls, or in attics. Watching for new droppings in areas that have already been cleaned up is one way to tell if there are still rats present. You may also see droppings from larger animals in attics; you should avoid contact with all animal droppings due to the risk of disease.

Gnawing Damage

Rats must gnaw constantly to keep their teeth short, and frequently gnaw to enlarge holes or gain access to structures. They may also gnaw through plastic or cardboard containers to access food contents. Gnawing damage usually looks like irregularly-shaped openings.


The figure to the right shows the track marks of rats (which differ on the front and back paw), and mouse tracks (which are much smaller) and have roughly the same front and back paw print.

Burrows or Holes

Norway rats create burrows or holes for nesting and storage. All rats may create holes to gain access to structures.


Signs of Rats Feeding

Rats sometimes drag food to a safe location to consume it, or cache food for later. They may leave piles of snail shells or other refuse in sheltered locations. You may see gnaw or bite marks on fruits, vegetables, or nuts. Roof rats often gnaw the peel from citrus fruits, leaving the flesh behind. When rats are indoors, you may see gnaw marks on packaged food in pantries.


If rats get inside your house or other structure, you may hear noises from the attic or walls, especially at night. You may also hear rustling in vegetation, especially trees, outdoors in the evening and morning.


Severe infestations may create odors from urine or droppings. A ‘dead animal’ smell is a clue that a rodent may have died in the walls or attic. The presence of flies indoors may also signal that rodents have died inside walls or attics.