Rat vs. Mouse: What’s the Difference?

Rats and mice look alike, however, there are a few differences. They are both rodents but from different species and subgroups. Here, we’ll discover the main distinctions between them, so you will know more about each kind:

  • Size – rats are generally much larger than mice.
  • Habitat – rats tend to live outdoors, while mice prefer to live inside.
  • Diet – rats are omnivores, while mice are mostly herbivores.
  • Behavior – rats are usually more aggressive than mice.

Overview of the Rat and Mouse

Rats and mice are two very similar, small rodents – but there are differences! Let’s explore them.

  • Rats have bigger bodies, up to 18 inches, and can weigh 500 grams.
  • Mice, on the other hand, are usually 5-7 inches long and max out at 60 grams. Rat fur is longer, their tails less so, and their legs and snouts more prominent. Color can vary.
  • Rats live up to 4 years, while mice only make it to 2.
  • Rats eat meat and plants, and mice snacks on seeds, nuts and fruit.
  • Rats are curious and explore; mice stay in safe places, making nests of paper or fabric.
  • Finally, rats are social; mice prefer to be alone, only looking for mates during breeding season.

Physical Appearance

Rats and mice may appear similar, yet there are some physical distinctions. Generally, rats are bigger and have longer tails, which are thicker at the bottom. They also have larger feet and more pointed noses. Mice, on the other hand, have smaller feet, pointed noses, and much shorter tails.

Let’s delve further into the physical discrepancies between rats and mice:


Rats are easily recognisable by their long, naked tails and bulky bodies. An adult rat can be 8-11 inches from head to tail and a Norway rat can weigh over 500 grams. They have longer snouts and thicker necks than mice.

Small eyes close together, big ears, and four sharp incisors that grow all their life. Their coats may be shaggy or even bald looking, and some species like the African pygmy rat have smoother coats.

Wild rats usually have dark grey or brown fur with lighter fur around the face, feet, and belly. Pet rats, however, come in many colors depending on breed, like black, white, and red-eyed cream.


Mice have elongated snouts and small ears. Their bodies are 3-4 inches long, with scaly tails that can be up to 1.5 inches. Adult mice usually weigh around 1/4 of an ounce. They are usually light grey to medium brown, but mutations can make them appear like rats – dark brown to black. Mice have snouts that are shorter and thicker than rats’, with shorter fur.

When startled, mice can jump up to 12 inches – a way for males to show off for female mates. Although they have poor vision, they rely on smell and hearing to detect potential predators. Unlike rats, mice don’t transmit many diseases that humans can contract. Still, pest control interventions are necessary for them as their urines create strong odours and they contaminate food sources.


Rats and mice are both rodents found in homes. However, they have distinct differences that must be recognised. One of these is their behaviour. To differentiate between rats and mice, let’s examine their behaviour more closely:

  • Rats are more active at night and tend to explore more. They are also more likely to gnaw on things like wires and furniture.
  • Mice are more active during the day and prefer to stay in one area. They are also more likely to find food sources like crumbs and spilled food.


Rats are part of the Rodentia order and Muridae subfamily. Commonly, there are two species: Brown Rats, also called Norway Rats or Rattus norvegicus; and Black Rats, known as Roof Rats or Ship Rats, or Rattus rattus. They are great at living in cities all around the world.

Rats are bigger than mice, with a thicker tail and longer ears. From snout to tail they usually measure 8-11 inches while mice measure 6-8 inches. Rats have bad eyesight but strong hearing, smell and touch. They’re more aggressive and easier to spot due to their size.

They mainly feed on grains, fruits and nuts. But, rats will eat almost anything they can get hold of. In colonies, there are loose social hierarchies, and male rats are usually the alpha males. They dominate resources such as food and mating. Rats may live together in groups in sewers and homes with large populations. Females can have up to 7 litters of 22 pups, if they have enough resources.


Mice are omnivores, eating any food they can find. Sweet or fatty items, such as cereal and cheese, are especially appealing. Even if the food isn’t tasty, they will eat it. They are very agile, able to fit through holes only a few millimeters wide. They can jump up to 2 feet high in one leap, and run across wires and cables.

Mice search for food and water near pantries and kitchen cabinets. They are mainly nocturnal, however they may roam around at any time of day. When detected, they tend to be scared, not aggressive. As mice have bad eyesight, they rely on their senses of smell and touch to explore their environment when hearing unfamiliar noises.



Rats and mice have very different preferences when it comes to their habitats. Rats usually nest outdoors, in the high branches of trees. They are good climbers. While mice are better at navigating tight spaces and corners, they prefer to nest inside.

Let’s explore the differences between rat and mouse habitats in more detail:


Rats are everywhere! From urban areas to near-desert conditions, and from the woodlands to the fields. Norway rats usually live on lower levels of buildings, like basements and ground floors. On the other hand, roof rats like to climb up walls and trees to get to rooftops. They’ll make themselves at home wherever they can, like couches, car seats, wall cavities and shelving units.

Rats prefer warm climates, but they can also survive in cold temperatures by creating burrows and collecting bedding material:

  • Creating burrows
  • Collecting bedding material


Mice are everywhere—except Antarctica! They are herbivores and eat mostly plants. There are wild types, like the deer mouse and woodland mouse, and a few domesticated mice too. House mice live with humans and adapt easily.

Mice live in fields, forests, meadows, mountains, and deserts. When food and shelter are scarce, they move into buildings. With no predators to control their numbers, house mice populations can quickly grow too large.


Rats and mice differ in their diets. Rats eat both plant and animal matter; they are omnivores. Mice, however, have more varied diets. Some species are purely vegetarian, whilst others opt for a balanced diet. Let’s delve deeper into the eating habits of each.

  • Rats eat both plant and animal matter; they are omnivores.
  • Mice have more varied diets. Some species are purely vegetarian, whilst others opt for a balanced diet.


Rats are omnivores and have diverse diets. They eat grains, fruits, veggies, and sometimes even small amounts of meat. Plus, they typically require larger servings than mice.

Each day, rats should have five tablespoons of grain-based products like cereal and bread, plus two tablespoons of fresh produce like spinach or carrots. For healthy fats, give them pistachios, peanuts, or peanut butter as a treat.

Rat owners must make sure their little friends get the nutrition they need for good health!


Mice are omnivores. In the wild, they eat seeds, fruits, grains, vegetation, and even insects like spiders, moths, and lizards. In captivity, they can have treats such as breads, cooked pasta, and oats. Pet food is also suitable. They require hydration, which is best provided with a dropper or a shallow dish.

Mice need food throughout the day, usually in the form of commercial chow or treats. Fresh vegetables every few days are important for health. Leafy greens should be given more often than carrots or cucumber, and only as treats. Insects can be part of their diet, but make sure they are free from pesticides.


Rats and mice have disparate breeding traits. Rats breed once or twice a year and can have litters of up to twelve babies. Mice, on the other hand, breed multiple times in one year and their litters can be much larger – sometimes several dozen! Rats are bigger than mice and live longer too. These facts contribute to their dissimilar reproductive habits.


The common rat is usually bigger than the house mouse. Both breed fast. They mate frequently, year-round. Females can birth litters of 4-12 pups every 3-4 weeks. Rats mature sexually at 6-12 weeks, while mice do it in 4-5 weeks. Rats live up to two years, but mice only up to one. Rat gestation is 21 days, mouse’s 19.

Blind and helpless, newborns nurse for 3 weeks ’til 10-14 days, then leave the nest. Females can have up to six litters in their life, producing an average of 72 babies from one rat!


Mice and rats differ in the realm of reproduction. Mice can reproduce at six weeks old, while rats take nine weeks. Each female mouse can have up to 10 litters a year, with 5-6 young in each. Female rats birth twice a year, with 6-8 young.

Pet mice usually live two years, while pet rats can survive 3-4 if taken care of.


When looking at the diseases rats and mice can spread, there’s both similarities and differences. Both rodents can transfer zoonotic diseases to humans, yet they differ in the type of diseases they spread. Let’s explore what kind of illnesses they can cause and how to stay safe from them.


Fancy rats and domestic rats are the two main types of rats kept as pets. Black rats, or ship/roof rats, don’t make good pets. They can carry diseases like bubonic plague and typhus, which can be dangerous to humans.

Fancy rats have small ears and no tail. Domestic rats have large ears and a long tail. They also have aggressive temperaments. Fully grown, fancy rats can be 7-11 inches long and weigh up to a half-pound. They usually live one to two years in captivity, but proper nutrition can extend their lifespan.

Pet rats can get respiratory illnesses from unsanitary living conditions or contaminated food. Signs include sneezing, labored breathing, discharge from nose and eyes, weight loss, irregular posture, and tremors. Emotional distress can also cause physical problems.

To help prevent disease transmission, pet owners should practice good hygiene after handling their rats. This includes washing hands before and after contact.


Mice can be dangerous! They can transmit diseases like Salmonella, Leptospirosis, and Tularemia. The Hantavirus Pulmonary Syndrome (HPS) is linked to a specific type of mouse. Though HPS cases are rare, it’s wise to take precautions if you live in an area with lots of mice.

  • Wear gloves when handling mice or their droppings.
  • Wear a mask when cleaning up their nesting materials.
  • Make sure food is stored in mouse-proof containers or cabinets. This stops animals from getting into it and safeguards humans from ingesting harmful bacteria from the rodent’s saliva or urine.


Rats and mice are often confused. But they have distinct features. Rats are bigger and have a longer tail. Their eyesight is also better than mice. They are slow-moving and like to roam.

Mice, however, are smaller in size with a shorter tail. Eyesight isn’t their strong suit. But they are nimble and used to living in tight spaces. So, if you’re looking for a pet or trying to identify a creature around your home, it helps to know the differences between rats and mice.