Rat vs. Mouse Identification: Which Is Eating Your Cheese?

By: Yara Simón  | 
Brown rat feeding in the trash in the street
Is this little dumpster diver a mouse or a rat? Jacques Julien / Getty Images

As it scurries past you, just missing your foot by centimeters, you probably aren't worried about the kind of rodent you just encountered. Instead, you're probably more concerned about escaping the situation unscathed.

Although they might — very fairly — elicit a similar response in you, rats and mice are two different species. Read on to learn more about rat vs. mouse distinctions.


Appearance: Sizes, Ears, Snouts and Tails

At first glance, rats and mice may look the same, but there are a few key differences. Though their size and weight depend on the type of species, rats are the bigger rodent of the two.

Brown rats, or Norway rats, are on the larger side, with their bodies measuring 7 to 10 inches (17.78 to 25.4 centimeters) and their tails adding 5 to 8 inches (12.7 to 20.32 centimeters). A black rat's body and tail are, on average, about 14 inches (35.56 centimeters) long.


A house mouse is smaller, with a body and tail that is about 5.5 to 7.5 inches (13.97 to 19.05 centimeters). It's easier to see the size difference between adult mice and adult rats; a younger rat might be the same size as an adult mouse.

Additionally, mice's ears do not look proportional to the rest of their body, but rats' do. Mice also have more triangular snouts, whereas the rats' are less pointy.

They also share some similarities. Both have long, thin tails, though there isn't hair on rat tails and there is on a mouse's. They can also be of similar colors, including gray, white and brown.


Separate Eating Habits

Mice teeth are not as strong as rats', meaning you might be able to more easily keep them from accessing food sources by securing items behind materials that house mice teeth cannot penetrate. You won't be as lucky with a rat.

A rat's diet includes more protein-rich foods like meat, but they will eat a variety of items. Mice tend to eat cereals, fruits and vegetables.


Similar Habitats, Different Lifestyles

Rat species are more social compared to mice. Black rats tend to stay in buildings near water and on ships. In places with tropical weather, they nest in overhead locations, like a tree or roof.

The Norway rat spends its time on the ground, particularly in sewer systems. Mice similarly spend time on the ground.


Distinguishing Rat Droppings From Mouse Droppings

Brown rat droppings are dark brown and appear tapered on each end. Meanwhile, the black rat's dropping curve. Mice droppings are black and easy to confuse for rat or cockroach droppings. These rodents can produce 40 to 100 droppings a day; rats come in at around 20 to 50 droppings a day.

Rodent droppings are dangerous, potentially transmitting diseases and viruses like Hantavirus pulmonary syndrome (HPS). Deer mice can transmit the respiratory disease.


Public Health Hazards

Regardless of if it's a rat or mouse, rodent infestations pose a threat to public safety. Seal up any holes that allow them to enter your home (steel wool can be surprisingly useful). Set traps to deal with your mouse or rat problem, but keep in mind that mouse traps will not work on rats, so set up the right kind of trap.

The Centers for Disease Control and Prevention advises against glue traps. "These traps can scare the rodents causing them to urinate, which can increase your chance of getting sick," according to the CDC.


For a more serious rodent infestation, you should seek help from pest control.