Evidence of Rat Infestations

Both Norway rats and roof rats thrive throughout the U.S. The Norway species tends to be solitary, but an infestation can still consist of up to 40 rodents in a single home. In contrast, roof rats are more social and will live in colonies of over 100 rodents. Signs of rats include visual, sound, and scent clues.

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Signs of Rats in the House or Attic

There are a number of ways to discover an infestation within a home, such as noticing:

  • Droppings - Fresh rat poop is black, shiny, and about the size of a raisin.
  • Noises - Homeowners may hear scratching, squeaking, and gnawing sounds coming from attics, crawl spaces, or walls.
  • Tracks-- Four-toed front feet and five-toed hind feet paw prints found in mud, dust, snow.
  • Rat hair - Shed fur may snag on rough wood or inside pantries and cabinets.
  • Smears and smudges - Oil from rat fur transfers to surfaces as the pests move.
  • Holes - Rats chew ragged openings in food packages and containers.
  • Odor - Rodents have a musky scent that gets stronger as populations grow.

Rat Poop

Although different kinds of rodent infestations require different means of treatment, many homeowners are unable to tell one scaly-tailed, scurrying pest from another. One of the easiest methods of differentiating between a rat problem and a mouse infestation is by looking at the pests’ feces. Fresh rat droppings look like raisins, with an elongated, spindle shape and dark black or brown coloring. After a couple of days, they harden and fade to dirty white. Mouse droppings have similar qualities, but are smaller, resembling dark grains of rice.

Rat vs Mouse Poop

As a rule, rat poop:

  • Measures about 1/3 of an inch in length
  • Appears similar in size to a raisin
  • Has one-pointed or tapered end

On the other hand, mouse feces:

  • Never exceed 1/4 of an inch long
  • Look like grains of rice
  • Have pointed ends


Norway rats and roof rats are the most prevalent species in the U.S. Similar in appearance, Norway rat droppings and roof rat droppings are known to carry disease-causing pathogens. Among the illnesses, these rodents can give to humans are the plague, leptospirosis, salmonellosis, typhus, tularemia, meningitis, and Hantavirus. The most common method of transmission is inhalation. When dried rat droppings are disturbed, these viruses often become airborne. Some, including Hantavirus, remain in the air for several days afterward. Rat diseases can also be spread through contaminated food, as the pests tend to eat and defecate in pantry items.


Oftentimes, rat sounds are the first indicators of rodent problems within the home. When indoors, these pests can be heard gnawing on floor joists, siding, and electrical wiring to grind down their front teeth. They also scamper within walls, commonly leading homeowners to misidentify them as larger pests. However, when the scurrying is paired with incessant squeaking, residents should assume the sounds are coming from rodents. Other rat noises include hissing and shrieking to ward off enemies.


Rat sounds aren’t the only indication of an infestation. The pests also contaminate nearly every surface they touch with trace amounts of fecal matter. Their search for food ranges from pantry items to pet food, garbage, and other animals’ droppings. Therefore, finding chewed open packages can point to thriving rodent populations.

The pests typically build their nests in wall voids and crawl spaces. Since dogs and cats are often attracted to areas of the home where rat noises are being produced, pets’ preoccupation with certain rooms sometimes leads homeowners to discover infestations.


Homeowners that hear scratching noises in the attic at night may be dealing with rats. These nocturnal pests typically enter homes through basements, subfloors, and hollow walls, though some species, such as roof rats, are particularly common in the attic. Noises at night, such as gnawing, clawing, scratching, or squeaking, are usually the result of rats communicating with each other.

Depending on their mood, these vocal pests make a variety of different sounds. Teeth chattering or clacking may indicate feelings of anxiety or contentment, while fighting rats can make a loud shrieking, hissing, or squeaking noise. In the attic, rodents may also keep homeowners up at night with sounds caused by their movement. As rats travel between their nests and food sources in kitchens, pantries, or bathrooms, residents may hear rustling or scratching overhead.


Known to infest homes during severe weather or when food is scarce, rats often utilize walls and voids within buildings for travel and nesting. These agile pests do the majority of their scavenging from dusk to dawn. Homeowners may discover infestations when they hear rat noises in the wall at night or in the early morning. While people can sometimes pick up the sound of rats squeaking in walls, it is more common to notice louder, more repetitive activities. These typically include rustling or scratching noises in the wall when the pests run, as well as thumping sounds that occur when they bump surfaces.

In addition, rats are notorious for chewing electrical wires and other dangerous household items. A gnawing sound in walls, when loud enough to detect, frequently signifies rat infestation. This can be cause for concern, as damaged wires are a serious fire hazard.


The easiest places to notice rat tracks are in snow, mud, and dust, so little-used basements and muddy areas around home foundations are good places to start. Searching for tracks may also help in the identification of how rats are getting into homes. Additionally, these pests establish regular foraging trails to move between their nests and food sources, so they often leave behind well-worn paths.

Rat tracks vary from about one-half to one inch in length and width depending on the individual pests’ age, size, and sex. Like most rodents, rats have four-toed front feet and five-toed hind feet. Unlike the tightly aligned toes on their back paws, the toes on their front paws are widely spaced in a circular pattern.

Rat footprints often have a smudged appearance, as only the front half of their paws typically leaves a clear imprint, and these are often obscured by their hind feet as the pests run. In addition to tracks, evidence of rats includes droppings, gnawed wood and plastic items, and greasy oil marks on walls.


During the springs and summer, rats create trails between outdoor burrows. However, as the winter sets in, many begin to invade homes. Warm spaces are favored places to overwinter, so homeowners may discover rat tracks in snow leading to exterior walls. Since paw prints left by rats, mice, squirrels, and a variety of other rodents can look very similar, utilize the expertise of the professionals at Trutech to help identify rat tracks and effectively deal with infestations.


Finding evidence of rats near lawns and gardens often means the pests have nests in outbuildings or under porches and decks. Signs of rats outdoors include:

  • Runways – Rats will travel repeatedly to food sources and leave worn trails in grass or mud.
  • Tracks – Footprints left behind in dust or moist earth can help residents find rodent nests.
  • Burrows – Holes about four inches wide leading into narrow tunnels are a specific sign of Norway rats.

Homeowners who find signs of rats in the home, yard, or attic should contact the pest control experts at Trutech for efficient rodent exclusion and removal.