Mice and Rats: How to Identify, Remove and Keep Out Rodents

You heard scratching in the wall, or you found small dark pellets in a kitchen drawer. Before you buy anything, figure out whether you have mice or rats, because the traps, the entry gaps and the amount of work are different. This page helps you identify the rodent, clean up safely and work through the steps in the right order.

Mice or rats? How to tell them apart

Adult mice and adult rats are easy to separate by size. The tricky case is a young rat, which can be mistaken for a mouse. Look at the head and feet: young rats have a large head and large feet for their body, while a mouse’s head and feet are small.

Our guides to house mice and deer mice and to Norway and roof rats go into more detail.

Signs you have rodents

You rarely see the animals themselves. You see what they leave behind:

• Droppings along walls, in drawers, under sinks and behind appliances.
• Gnaw marks on food packaging, wood or wiring.
• Dark, greasy rub marks along the paths they travel.
• Shredded paper, fabric or insulation bundled into a nest.
• Scratching or scurrying at night in walls, ceilings or the attic.
• A musky smell in closed spaces.

To tell an active problem from an old one, and to tell rodent droppings from cockroach or bat droppings, see signs of rodents.

Health risks

Rats and mice can spread disease through their droppings, urine, saliva and bites, and through contaminated food. The CDC lists hantavirus, salmonella and leptospirosis among the illnesses rodents can pass to people. Hantavirus spreads mostly when you breathe in dust from stirred-up droppings, urine or nesting material. Fleas, ticks and mites that feed on rodents can carry other diseases.

That does not mean every mouse in the pantry is a health emergency. It does mean you should handle cleanup with care.

What to do first: the order of work

Rodent control works best when you follow this order. Skipping straight to poison is the most common mistake.

1. Inspect. Find where the droppings, gnaw marks and nests are. That tells you what you have and where to set traps.
2. Take away food and shelter. Store food, pet food and birdseed in sealed metal or heavy plastic containers. Clear clutter in garages and storage areas.
3. Seal entry points. Mice fit through gaps about 1/4 inch wide; adult rats through about 1/2 inch. Use steel wool, metal and concrete, not foam alone. Our rodent-proofing guide has a full checklist.
4. Trap. Snap traps set along walls catch most indoor rodents. Keep trapping until you catch nothing for a week.
5. Consider bait stations last. Consumer rodent baits must come in a ready-to-use bait station. Poison in the house can leave dead rodents in walls, and it puts pets and wildlife at risk. Compare your options in traps vs. bait stations.

How to clean up droppings safely

Do not sweep or vacuum dry droppings. That can put virus particles into the air you breathe. Wet them first, wipe them up, then disinfect.

The CDC’s cleanup steps, in plain terms:

1. Open doors and windows for 30 minutes before you start, and stay out of the space while it airs out.
2. Put on rubber or plastic gloves.
3. Spray droppings, urine and nesting material with a disinfectant, or with a fresh mix of 1 part household bleach to 9 parts water, until very wet. Let it soak for 5 minutes or as long as the label says.
4. Wipe it up with paper towels and throw them in a covered trash can.
5. Mop or wipe floors, counters, cabinets and drawers with disinfectant.
6. Wash your gloved hands, take the gloves off, then wash your bare hands with soap and warm water.

For dead rodents and used traps, double-bag them, tie each bag shut and put them in a covered trash can. Heavy infestations call for more protection, including a respirator with HEPA filters.

When to call a professional

Many mouse problems are a weekend job: seal the gaps, set a dozen or two snap traps, clean up. Get professional help when:

• You have rats inside the living space, or signs of a large or long-running infestation.
• Rodents are in places you cannot reach safely, like wall voids, a crawl space or a high roof line.
• You have trapped for several weeks and still find fresh droppings.
• You cannot find or reach the entry points, or sealing them needs ladder work or masonry.
• Someone in the home has a weakened immune system, or the cleanup involves a heavily soiled attic or crawl space.

A good provider will inspect, explain where rodents are getting in and seal those gaps, not just put out bait. Ask to see their state pesticide license. Our guide to choosing a pest control company covers the questions to ask.