Adapted from Identifying a Mouse or Rat Problem with permission from Tomcat

The first step to getting rid of mice or rats is figuring out which rodent you're dealing with - and how many there are. Before you take any steps to control a rodent problem, be sure to inspect the premises inside and out. Conducting a thorough inspection will be critical for helping you decide which method of control is right for you.


 

 

The Inspection

A good home inspection will help you determine the type of rodent you're dealing with, their patterns of activity, what's bringing them inside your home, and most importantly – which rodent-control product to use for eliminating them. A good inspection will help you determine:

• The type of rodent - is it a house mouse, Norway rat or roof rat?
• The severity of the problem
• Where they eat, travel, and nest
• The cause of your problem - whether it's poor sanitation, available food, or water
• The best type of rodent control product to use and where to place it for success

To conduct an inspection, use a flashlight to examine dark areas where rodents like to hide. Be sure to look up, down and all around for signs where rodents travel.

 

Tell-tale signs of rats and mice include:

1. Rodent droppings are a sure sign that rats or mice are present, and will indicate the type of rodent, the size of the infestation, and where they are most active. 
   - Mouse droppings are small, less than one quarter inch, and pointed on both ends.
   - Rat droppings are half an inch or larger. Norway rat droppings are blunt at both ends, while Roof Rat droppings are have pointed ends.
   - New droppings are shiny and putty-like in texture, while old ones are hard and crumbly.
   - Varying feces sizes indicate that juveniles and adults are present, and lots of droppings may be an indication of a large infestation.
   The location of any of these droppings indicates active areas where you should place bait or traps and the type signifies whether to place rat or mouse traps/products. 

1. Rodent urine has a strong musky odor. With large infestations you can easily smell it. 
2. Gnawed holes of a mouse are small, clear-cut, and about the size of a dime. Gnawed rat holes are large, about the size of a quarter, with rough torn edges. 
3. Oily rub marks are left in places where rodents travel along walls. If rub marks smear, you know they are fresh. Gnaw marks on wood around the house also are a sign. Tooth marks about one eighth inch long are typical of rats and small scratch marks are a sign of mice. 
4. Common rodent pathways are generally along interior walls, building foundations, ledges, pipes, electrical wires, conduits, tree branches and fence rails. 
5. For nesting, Norway rats burrow deep in the ground outdoors. Roof rats typically nest above ground in attics, trees, or dense vegetation. Mice will shred paper, string, and other pliable materials to build their nests indoors. 
6. Scratching sounds at night can indicate that rodents, which are nocturnal, are scampering around inside walls and along floors 
7. Pets tend to act unusual when they hear or smell rodents in the house. They may appear extremely alert, bark, or begin to paw at spaces beneath refrigerators, stoves, or low-clearance pieces of furniture. 

Identifying the correct rodent culprit and understanding their behavior can help you select the right rodent control solution and help prevent future infestations.