Signs You Have a Rodent Infestation

6 Signs of a Possible Rodent Infestation

Key Takeaways:

• Gnaw marks and droppings are some of the most concrete clues you will find. Rodents can’t help but leave them behind.
• Rodents do their work after dark. Unexplained noises from the attic or walls are a major indication.
• Check the quiet corners. Rodents establish their hideouts in low-traffic areas. Your investigation should focus on attics, basements, and crawlspaces.
• Greasy streaks along baseboards reveal the routes rodents use to navigate your home.

Are you worried about rodents setting up residence in your home? When dealing with rats or mice, you have to think like a detective. Look for the clues they leave behind. Rodents are experts at staying hidden, but they always leave a trail of evidence. By learning to spot these six signs of a possible rodent infestation, you can determine the next steps to take back control of your property.

These are the top six signs of a rodent infestation:

1. Rodent Droppings
2. Gnaw and Chew Marks
3. Nests and Scavenged Nesting Material
4. Rub Marks and Tracks
5. Strange Sounds in the Night
6. A Live Rat or Mouse

How to Identify a Rodent Infestation

#1: Rodent Droppings

Finding droppings is often the first sign people find. Never handle droppings without protective gloves. They can carry a wide range of bacteria and viruses, so the area must be carefully disinfected.

Mouse droppings are small (⅛–¼ inch), and have a pointed, seed-like shape. Rat droppings, on the other hand, are much larger (½–¾ inch), thicker, and often have blunt, rounded ends.

• Common Hotspots: Search in protected locations that are close to food or warmth. Prime locations include behind the stove or refrigerator, under sinks, deep inside cabinets or the pantry, and along the baseboards in seldom-used rooms.
• Risk Assessment: High. Droppings are undeniable proof of an active infestation and present a direct health hazard.

#2: Gnaw and Chew Marks

A rodent’s teeth grow constantly, compelling them to chew on hard surfaces to file them down. This behavior leaves behind a trail of destruction that is a clear indicator of their presence.

The size of the marks tells the story. Mice leave behind fine, scratch-like grooves. Rats have much stronger jaws and create deeper, rougher gouges, even on materials as tough as wood, plastic, and soft metals.

• Common Hotspots: Check food packaging, especially bags of grain or pet food, which are among rodents’ favorite foods. Also, inspect baseboards, door frames, and furniture legs. Most critically, look for damage to electrical wiring, which poses a serious fire hazard.
• Risk Assessment: High. While property damage is a concern, the potential for a house fire from chewed electrical wires makes this a critical threat.

#3: Nests and Scavenged Materials

They use any soft material they can find, such as shredded paper, fabric, pulled-apart insulation, and plant debris, to build their hideouts.

A mouse nest is typically a small, messy-looking ball of finely shredded material. A rat nest is larger and more robust, often with a more organized structure separating sleeping and food storage areas.

• Common Hotspots: Rats prefer secluded, undisturbed locations like attics, basements, and deep within crawlspaces. Mice may also nest in these areas but are just as likely to be found inside wall voids or behind large appliances.
• Risk Assessment: High. A nest is proof of a breeding population. The problem will only grow larger and more difficult to solve if left unaddressed.

#4: Rub Marks and Pathways

Rodents are creatures of habit and prefer to use the same routes repeatedly. They stick close to walls for security, and over time, the oil and dirt from their fur create dark, greasy smudges along their paths. The main evidence here is the “rub mark” itself — a dark smear on a surface.

In dusty, untraveled areas, you might also spot tiny footprints or tail marks. To confirm a suspected path, sprinkle a thin layer of flour on the floor at night and check for fresh tracks in the morning.

• Common Hotspots: Inspect the bottom of walls and baseboards, especially in corners. Also, check along pipes, rafters in the attic, and foundation ledges in the basement.
• Risk Assessment: Medium. This is definitive proof of rodent traffic patterns. While not a direct danger itself, it confirms an active infestation and shows you the scale of their movement throughout your home.

#5: Strange Sounds in the Night

Your home is quietest after dark, which is when rodents are most active. Unexplained noises coming from the ceiling or walls are often one of the first clues homeowners notice.

You’re listening for sounds that are different from the normal creaks of a house settling. The most common rodent sounds are scratching, light scurrying, faint squeaking, and a distinctive gnawing or chewing sound.

• Common Hotspots: These sounds are most frequently heard coming from the attic (above your bedroom ceiling) or from within wall voids, where rodents travel unseen.
• Risk Assessment: Medium. While noises strongly suggest an infestation, they require you to find physical evidence to confirm it. Consider noises your cue to start looking for the other clues on this list.

#6: A Live Rat or Mouse

Because they are naturally secretive and avoid humans, a sighting is a sign that should be taken very seriously. A rodent seen scurrying across the floor is a bad sign. If you see one during the daytime, it can indicate that their hidden nests are overcrowded, forcing them out in search of resources.

Here in Michigan, the common rats in homes are black rats and Norway rats. If you have mice, it’s likely house mice. We also have deer mice in the area, but they typically remain outdoors.

• Risk Assessment: Critical. A single sighting almost always means there are many more you don’t see. It is a sign of a well-established infestation that requires immediate professional intervention.

If You Have a Rodent Problem, Get Help Fast!

If your investigation has turned up one or more of these clues, you have an active rodent problem. The good news is that you’ve identified the issue, and now you can take the most important step.

We highly recommend bringing in professionals to handle the situation. Our local rodent exterminators will perform a complete inspection to determine the full scope of the infestation and implement a safe and effective solution.

For a thorough inspection or a complimentary estimate, contact the experts at Griffin Pest Solutions today.