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Although rats and mice are very similar in many ways, they are two completely different animals. But how do you tell the difference between mice and rats? We explain the essential features.

In a nutshell

  • the biggest difference between rat and mouse is the size of the body and body parts
  • Feeding habits are good for recognizing the species even without individuals present
  • There is a high risk of confusion with mice, especially in young rats due to numerous similarities

The difference between rats and mice

From obvious to only recognizable at second glance, numerous details paint a clear picture of when you have rats or mice in front of you. We assume the black rat (Rattus rattus) and the house mouse (Mus musculus) as these animals are most commonly found in the home. In addition, these two species have the greatest similarities and thus potential for confusion.


The size

Probably the most obvious difference is the size of the animals:

  • Mouse 3 to 10 centimeters body length
  • Rat: around 18 to 23 centimeters body length

The body size is initially based on the head-torso length. In addition, there is the tail, which roughly accounts for the length of the body in both species.

Notice: If an adult mouse encounters a young rat, the almost identical size can actually quickly lead to confusion. Therefore, only the interaction of numerous features leads to clear identification!

The relations

Not only the absolute dimensions, but also the ratios of the individual body parts to each other can serve as a clear distinguishing feature. Compared to the actual body, the head and paws of the mouse are significantly larger than those of the rat.

The physique

Due to the difference in body size, the physique of the animals is clearly different. The smaller mouse is usually much more compact and stocky than the slender, elongated black rat.


Notice: A well-fed rat can still appear stocky, while an emaciated mouse can appear significantly slimmer than a normal rat. Therefore, this feature should always be considered in connection with the size and relation of the body parts to each other!

The fur color

Colors are usually a very recognizable indicator of whether you are dealing with rats or mice:

  • Mouse: light gray to brown coat color, usually lighter belly
  • Rat: Dark gray fur with a uniform color all around

The tail

Long, thin, mostly hairy tails in the mouse can be clearly distinguished from the usually bare, scaly tails of the rat.


The footprints

The distinction between mouse and rat tracks can initially be made on the basis of the sheer size. In addition, however, mice show themselves primarily as animals that appear with their full foot. The track is therefore clearly and completely recognizable. Black rats, on the other hand, tend to walk on tiptoe. Your impressions are therefore incomplete. Often only the forefoot is pushed off clearly and distinctly.

residence and nesting sites


  • Ground level lifestyle
  • Building nests in burrows, under sheds, floor slabs, etc.
  • If necessary, it can also be climbed


  • No specialization in certain areas, today often found close to civilization
  • Nest building mainly under roofs, as well as in other places protected by height (in nature also on trees, tall bushes, etc.)

food and eating habits

Even if rats and mice accept the same food, their preferences and the type of consumption differ significantly:


  • prefers dry, starchy foods, such as cereals and other grains
  • remove husks of grain and grind endosperms with teeth
  • Foraging recurrently in the same places
  • no urgent need to drink water


  • prefers moist foods, such as fruit, but also meat, etc.
  • bite through grain kernels so that coarse residues remain recognizable
  • Foraging in the area without recurring feeding places
  • drink about 30 milliliters of water per day

frequently asked Questions

How do I tell the difference in other rat species?

In addition to the black rat, the brown rat is the most common. With a body length of around 30 centimeters and a very dark, often almost black coat pattern, it can be clearly distinguished from the native mouse species at first glance. Finer distinguishing features are therefore hardly necessary.

Do greasy goo belong to rats or mice?

A high fat content is typical for rat fur. When the animals crouch, crouch or even sit up, the fur leaves easily recognizable greasy traces on smooth surfaces.

Is there a difference between mouse and rat damage?

It is not possible to say in general which of the animals causes greater damage. Both species like to gnaw and leave clearly visible damage to buildings and facilities when foraging and building nests. Only the size and the place where it was found (cf. preferred whereabouts) allows a conclusion to be drawn about the animal species that caused it.

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