Mice are small, elusive, and surprisingly skilled at sneaking into homes without being noticed. By the time many people realize there’s a problem, a small population of mice may already have settled in. Understanding the signs of a potential infestation can help you take action before it becomes a bigger issue. If you’re not sure whether you’ve got a few uninvited guests scurrying about, here are some common indicators to watch for.

Unusual Noises in the Night

Mice are mostly active after dark, so it’s often easier to detect their presence when the house is quiet. If you’re hearing soft scratching or scurrying sounds coming from behind walls, in ceilings, or beneath floors, that’s a strong hint that mice might be nearby. Sometimes these noises are faint and intermittent, but if they persist over several nights, it’s worth investigating more closely.

Droppings and Urine Marks

One of the most obvious signs of a mouse problem is the discovery of small, pellet-like droppings. These droppings are usually dark and about the size of a grain of rice. You may find them in kitchen cabinets, drawers, pantry shelves, or along baseboards. Mice tend to leave droppings wherever they travel, so an increase in these tiny pellets can indicate that multiple mice have set up camp. In addition, you might notice a slightly musky odor coming from corners or cabinets. Mice leave urine trails that have a distinctive scent, which can become stronger as their presence increases. While you may not always detect the smell immediately, it often becomes noticeable over time.

Gnaw Marks on Surfaces

Mice need to gnaw continuously to keep their teeth from growing too long. As a result, you might find evidence of their chewing habits on various surfaces. Look for gnaw marks on wood, cardboard boxes, food packages, and even plastic containers. These marks are often small and rough around the edges. If you see tooth marks on items you’ve stored or use frequently, it’s a clue that something is nibbling away when you’re not looking.

Damaged or Missing Food

Mice are opportunistic feeders. They’ll take advantage of any accessible food sources, such as cereal, grains, pet food, or treats that haven’t been sealed properly. If you’ve noticed small holes in food packaging or discovered that something has been nibbling at the corners of a bag of flour, that’s a strong indication of mouse activity. Even small amounts of missing food can signal their presence.

Nests and Hidden Debris

Mice build nests from materials they can gather—paper, fabric scraps, dried plant matter, and insulation are all fair game. These nests are usually hidden in out-of-the-way places such as behind appliances, in the back of storage closets, inside drawers, or beneath furniture. Keep an eye out for small piles of shredded materials that don’t seem to belong there. Finding a nest confirms that mice have established a home base inside your walls or living areas.

Tracks and Smudges

In dusty areas, you might spot tiny footprints or tail marks on surfaces. Mice leave tracks that are often most visible along routes they travel frequently—along walls, corners, or near food sources. Over time, these critters also leave behind smudge marks caused by the oil and dirt on their fur rubbing against surfaces. While these signs can be subtle, they’re more evidence that mice may be roaming around after dark.

Pet Behavior Changes

If you have a cat or dog, pay attention to changes in their behavior. Pets have a heightened sense of smell and hearing, so if your four-legged friend is suddenly fixated on a particular wall, corner, or cabinet, there might be a good reason. Persistent sniffing, pawing, or barking at certain spots in the house can mean your pet is detecting something you can’t see.

Taking the Next Step

If you’ve noticed several of these warning signs, it’s time to consider your options. Mice breed quickly, so an initial problem can become more severe if left unchecked. Start by sealing cracks or gaps around doors, windows, and foundation lines. Keep food sealed in airtight containers and declutter storage areas to remove hiding places. Setting a few traps in areas where you’ve seen droppings or heard noises can help confirm whether mice are present.

If the problem continues or grows worse, reaching out to a professional may be the most efficient way to address the issue. By recognizing the early signs of a mouse infestation, you can take steps to protect your home, keep it clean, and ensure that these small but troublesome creatures find somewhere else to settle.