Telltale Signs of a Rodent Infestation: Do You Have Rats or Mice?

How to Tell if You Have Mice or Rats

• Rodent droppings are a good indicator of the pest in your house. Rat droppings are shiny black and 1/2 - 3/4 of an inch long, whereas mice droppings are small and smooth with pointed ends.
• Chew marks are another telltale sign to distinguish your rodent. Typical rat teeth marks are 1/8-inch long, while smaller and "scratchier" marks usually indicate mice.
• Chewed food, boxes, or trash in your kitchen could indicate rodents. While both rats and mice will eat anything, mice have a preference for cereal grains.
• Squeaks and scratching may also signal rodents in your home. Rats typically make gnawing noises, and you’ll hear them higher up in attics, roofs, or fence tops. Mice can be distinguished by squeaks and their preference to get inside walls and ceilings.
• Check for nests. Mice typically nest near heat sources such as ovens, refrigerators, and water heaters, and make nests of paper or fibrous materials. Roof rats will nest high up in attics and rafters, and Norway rats prefer to nest in basements or the ground floor of buildings and homes.

For more on how to identify different types of rodents, see our detailed guide to identifying mice and rats.

Rodent Signs: What to Look For

Rats and mice often leave unique signs. Before you set bait stations or rodent traps, ask yourself these 7 questions to determine whether or not you will need pest control in the near future:

1. Is your dog upset?

Dogs can become disturbed when they hear and smell rodents in the house. You may notice that your dogs pay extra attention to the fence line of your yard, especially at night when mice are more active. A bit of warning: don't rely on your dogs to rid the house of mice or rats. Dogs have very different immune systems than cats and may not be able to handle some of the diseases that rats and mice often carry.

2. Are rodent droppings present?

Stumbling upon a pile of rodent poop is less than pleasant, however, they can be helpful when trying to determine which type of rodent you have and what the next steps are in finding a pest control solution. If you notice multiple, distinct piles or tracts of what looks like dirt in your house, especially along walls, take a closer look to determine if it might in fact be rat or mouse droppings.

3. Do you see small tracks and tail trails in dusty areas?

Tiny footprints or lines from tails dragging will appear in dusty areas. Check along baseboards, in corners and near sources of food. You may even be able to determine a rodent's entrance and exit points by following these marks.

4. Do you see areas where wood or drywall has been gnawed?

Since their teeth never stop growing, both mice and rats are avid chewers. Typical rat teeth marks are 1/8-inch long. Smaller and "scratchier" marks usually indicate mice. Check along baseboards, door frames, doors, inside cabinets and anything that serves as a barrier to get behind walls. If you're hearing noises inside your walls, check the back panels of cabinets to try to find the rodent's access point.

5. Do you see smears along baseboards and other areas?

Rats and mice tend to stick near walls and borders when moving. If you are noticing greasy smears along baseboards or the bottoms of your walls, you may have some very unwanted visitors. Of course, marks can appear from other sources as well, so if you're noticing marks, try keeping the areas clean and see if the marks reappear.

6. Is there a heavy musky odor in the house?

Like all animals, rodents leave behind a distinct smell. If your house is suddenly smelling musky and no amount of open windows or fans seems to get rid of that terrible odor, then it's time to consider pest control. Rats and mice can quickly build nests and reproduce which will only add to the smell.

7. Are you hearing strange noises like scratching and squeaking?

Due to their nocturnal nature, you're much more likely to hear (and even see!) mice and rats at night. If you have a rodent infestation in your house, you will more than likely hear them moving and scratching in your walls and squeaking as they go. You may even spot them scurrying across the floor or along the wall if you're up late.

If you answered "yes" to the majority of these questions, you very likely have a mouse or rat problem on your hands. It's now time to explore some pest control solutions for this problem.

Steps for Rodent Control

First of all, don't feel overwhelmed. You can work to clear your house of rodents and take steps to keep them out.

Remove Food Sources

Start by putting away all food, including dog food, in secure containers and thoroughly cleaning floors and counter surfaces. Then pick the right rodent control product or combination of products to eliminate your mouse or rat problem.

Kill Rodents with Bait Stations

Baits are a highly effective way to control mice and rats. Each 1-ounce bait block in a Tomcat® Mouse Killer Child and Dog Resistant, Disposable Station kills up to 12 mice*, and each 4-ounce bait block in a Tomcat® Rat & Mouse Killer Child & Dog Resistant, Disposable Station kills up to 10 rats*. Since rodents feel secure in the station, they're enticed to eat the bait. However, a bait station is not a trap. The rodent enters the station, nibbles on the bait, leaves, and normally goes back to its nest where it dies a day or two later. Tomcat offers bait stations for both indoor and outdoor use, as well as stations that are resistant to child and pet tampering. For small rodent problems, use a pre-loaded, disposable station, but for larger rodent issues, select a refillable bait station for rats or mice instead.

Catch Mice and Rats with Traps

Mechanical traps can be used by themselves or in combination with baits for a comprehensive rodent control plan. One advantage that traps have over bait stations is they give you a visual confirmation that a mouse or rat has been caught. There are several trap options to choose from depending on your needs and preferences.

If your intruders are rats, you'll need a heavy-duty snap trap, like the Tomcat® Secure-Kill® Rat Trap. For mice, use the Tomcat® Kill & Contain® Mouse Trap if you want an easy way to dispose of the dead mouse without even having to see it. It's also specially designed to prevent paws and fingers from being snapped. For a more traditional mouse snap trap, use the Tomcat® Press 'N Set® Mouse Trap with its one-touch set. For a catch-and-release option, try the Tomcat® Multi-Catch Mouse Trap. 

Always wear gloves when handling baits and traps because rodents could be wary of them if they detect human scent. Place them in areas where you've seen signs of rodent activity such as near droppings or along walls with greasy streaks. Be sure to follow all label instructions for safe handling and how to set your baits and traps.

*Based on no-choice laboratory testing