Mouse & Rat Identification

What are mice & rats?

Mice and rats are both types of rodents and creatures that invade our Pleasanton homes and businesses. They, as with all rodents, have front teeth that constantly grow throughout their lives. Though they are similar, it is important to remember that mice and rats are two totally different species and knowing the differences between the two is important.

In general, adult mice are much smaller than adult rats. The size difference, however, may be difficult to spot between a young rat and an adult mouse. Mice have little triangle-shaped heads, and rats have large, blunt heads. Mouse ears relative to their head size are large, while a rat’s ears relative to their head size are smaller. Mice have a tail covered in a light layer of fur; rats have a naked scaly tail. If you have rats in your home, you will more than likely find grease marks on walls and furniture. Mice do not produce grease markings but do create a musty odor near their nesting site.

Listed below are the most common species of rodents in our area.

White Footed Deer Mice

  • Color: Brown with light feet and underbelly
  • Shape: Round
  • Size: 2 3/4 – 4 inches long
  • Region: Found throughout the U.S.
  • Habits: Deer mice are most often found in old fence posts, log piles, tree hollows, abandoned bird nests and beneath decks. During the winter months, they may invade homes, sheds, garages, or rarely used vehicles. When inside, they are known to make their nests in stuffed furniture, wall voids, storage boxes and tight areas in basements or attics. Deer mice prefer eating insects, nuts seeds, small fruits, and berries.
  • Threats: Deer mice are a common carrier of Hantavirus which is primarily transmitted by inhaling dust particles contaminated with the urine, feces, or saliva of infected deer mice.
  • Prevention: Mice are known to hide in clutter, so store boxes off the floor and keep areas clear. Pay close attention to areas where utilities and pipes enter the home and be sure to seal cracks and holes on the outside of your home. Keep food in sealed, rodent-proof containers. Make sure to keep tree branches and shrubs cut back from the house. Regularly inspect rarely used cars/RV’s, basements, and attics.

House Mice

  • Color: Dusty gray with a cream belly
  • Shape: Round
  • Size: 2 1/2 – 3 3/4 inches long
  • Region: Found throughout the U.S. and the world
  • Habits: House mice typically live-in structures but can survive outdoors, too. They prefer nesting in dark, secluded areas and often build nest out of packing materials, wall insulation, paper products, cotton, and other fabrics. House mice are excellent climbers and are able to jump up to a foot high.
  • Threats: Not only are house mice a nuisance but they can also cause serious property damage by chewing on materials. These mice have been known to spark electrical fires by gnawing on wires both inside homes and behind walls. Known to eat and contaminate food, house mice can transfer Salmonella, tapeworms, and the plague (via fleas).
  • Prevention: Mice are known to hide in clutter, so store boxes off the floor and keep areas clear. Pay close attention to areas where utilities and pipes enter the home and be sure to seal cracks and holes on the outside of your home that are ¼ inch in diameter or larger. Keep food in sealed, rodent-proof containers.

Norway Rats

  • Color: Brown with scattered black hairs; gray to white underside
  • Shape: Long, heavily bodied, blunt muzzle, small ears and eyes
  • Size: 7 – 9 1/2 inches long
  • Region: Found throughout the U.S.
  • Habits: Norway rats are typically nocturnal. Outdoors, they burrow in soil near riverbanks/ streams, under concrete slabs and piles of garbage. Indoors, they will often nest in basements, undisturbed materials, or piles of debris. To obtain food or water, they will gnaw through almost anything, including plastic or lead pipes.
  • Threats: Through their gnawing and eating, Norway rats can cause damage to structures and personal property. They can also spread diseases, including rat-bite fever, cowpox virus, plague, trichinosis, and salmonellosis. These rats can also introduce mites and fleas into a home.
  • Prevention: Norway Rats are known to hide in clutter, so store boxes off the floor and keep areas clear. Pay close attention to areas where utilities and pipes enter the home and be sure to seal cracks and holes at least ½ inch in diameter on the outside of your home. Keep food in sealed, rodent-proof containers. Keep kitchen floors and counters clean. Inspect your home for rodent droppings, damaged goods and gnaw marks.

Roof Rats

  • Color: Brown with black intermixed; gray, white or black underside
  • Shape: Long and thin with scaly tail; large ears and eyes
  • Size: 6 – 8 inches not including tail
  • Region: Coastal states and the southern third of the U.S.
  • Habits: Roof rats are primarily nocturnal. These rats live in colonies and prefer foraging for food in groups of up to ten and frequent the same food source time after time. They will also follow the same path to their food from their nest. Their runways may have dark rubs from where the fur makes contact and are typically free of debris.
  • Threats: Roof rats and their fleas have been historically associated with the bubonic plague. They can also spread jaundice, rat-bite fever, typhus, trichinosis, and salmonellosis.
  • Prevention: Roof rats are known to hide in upper areas, so to prevent roof rats for entering a home, seal up any holes or cracks larger than a quarter inch in diameter. Pay close attention to areas where utilities and pipes enter the home home and be sure to seal cracks and holes on the outside of your home. Keep food in sealed, rodent-proof containers. Make sure to keep tree branches and shrubs cut back from the house. Regularly inspect rarely used cars/RV’s basements and attics.

Are mice & rats dangerous?

Mice and rats are both dangerous and should never be inside any home or business. Rats and mice spread salmonella, E. coli, and many other disease-causing pathogens that make people sick.



Rats have large, strong jaws and can cause more significant damage than mice. Rodents cause damage by chewing through wires, pipes, drywall, and other structural elements. Mice and rats can trigger short circuits and fires. Personal property is often damaged by rats and mice chewing on clothing, upholstered furniture, rugs, boxes, and food containers.

Why do I have a mouse & rat problem?

Rats and mice are both opportunistic pests and have learned that our indoor and outdoor spaces provide them with resources that make their lives easier — access to food, safe shelter, and safety from harsh weather.



These rodents thrive in urban areas as the dense populations of people and structures allow them to have plenty of access to food, moisture, and nooks and crannies to hide in; this is not to say that these critters aren’t problematic in rural areas and the suburbs. Mice and rats will make themselves at home wherever they can.

Where will I find mice & rats?

Rats nest in woodpiles, dumpsters, gardens, fields, next to rivers, beneath building foundations, and in trees, shrubs, and on rooftops. Mice frequently nest under woodpiles, in areas of dense vegetation, in tall grass, under trees, and in tree cavities.



Inside homes and other structures, mice and rats tend to hide in secluded low-traffic areas, preferring to stay out of view. Basements, attics, kitchens, and bathrooms are areas of a home where rats and mice nest. They like to take up residence behind large appliances, wall voids, the backs of cabinets, and areas under sinks.

How do I get rid of mice & rats?

If you are ready to get rid of rats and mice from your property, reach out to the local pest control experts at Patriot Pest Management. Our customized services performed by our knowledgeable and friendly experts eliminate pests and stop them from coming back.



At Patriot Pest Management, we won’t hesitate to go the extra mile to ensure that our customers are happy, and their properties are free of pests. For exceptional home pest control or commercial pest control services in the Greater Bay Area and surrounding counties of California, contact Patriot Pest Management today!

How can I prevent mice & rats in the future?

Below are some easy-to-follow tips that will help you to keep rats and mice from taking over your home and yard:

  • Stop mice and rats from digging through your trash for their next meal by placing locking lids on trash cans.
  • Inside, get rid of food that rats and mice can take advantage of. Wipe down counters and regularly sweep floors. Take the trash out daily and keep lids on trash cans.
  • Remove bird feeders from your yard.
  • Eliminate water sources for rats and mice by repairing leaky pipes, clearing clogged gutters, and fixing low lying areas in your yard.
  • Get rid of debris from your yard that rats and mice can burrow in, such as brush piles, fallen trees, woodpiles, and overgrown vegetation.
  • Fill any holes near the foundation of your home or other structures on your property to prevent rats from burrowing underneath.
  • Seal spaces in the foundation and exterior walls of your home. Make sure to place covers over screens and vents.

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