Rats Vs Mice - How To Tell The Difference

A rodent infestation of any type is an unpleasant experience. However, knowing your adversary is critical when deciding the right course of action to eradicate the infestation.

Rodent infestations are a global problem, and the two main perpetrating species are often confused. This confusion can make the matter worse, as the behavioural and physical differences between the species mean that treatments that work for one species will often not affect the other.

Knowing the nature of your infestation is the first step in achieving a successful outcome.


The Main Species of Rats and Mice

The main source of infestations can be traced to three species of rats and mice – Brown Rat, Black Rat, and House Mouse. Although, the situation when it comes to the house mouse is complicated by sub-species found around the world.

However, for the purposes of this guide, we will stick to the common classifications as the differences are minor in nature.

Our service technicians can provide you with a high quality service and support to deal with your rat problem using nothing but the best quality products and latest techniques. We Guarantee you will receive a personal service and advice every step of the way. 

Telling Rats and Mice Apart Visually

Their shared genetic heritage has given the species some similarities. Common features shared amongst them include long tails, short legs, incisor teeth, whiskers, etc.

However, the differences are pronounced enough that if you happen to get a good sighting, then identification is relatively easy.

Identifying House Mice

The most obvious difference between mice and rats is the relatively diminutive size of mice. One proviso when making a visual identification based purely on size is that a house mouse can easily be misidentified as a young rat or vice-versa.

The following points can help distinguish between a young rat and a mouse:


Rats are generally a darker shade than mice which are usually grey or brown with lighter coloured fur on their underbelly.

Ears and tail

An adult mouse will have larger ears and a longer tail in comparison to its body size than a young rat.

Head and feet

A young rat will have a larger head and feet when compared to a house mouse.

Identifying Rats

Once again, size is the most obvious difference. Put simply, if the rodent is larger than 10cm in length, then in all likelihood, it is a rat. The only question left to resolve is the species of rat. In all probability, throughout most of Ireland, if you have a rat problem, it will be the brown rat. 

This can be confirmed by the following features:

Brown Rat

Black Rat

Other ways to differentiate between rats and mice

The very nature of a rodent infestation means that we don’t always have the luxury of a visual sighting to aid identification. However, there are many other ways to determine the culprit species.

However, the differences are pronounced enough that if you happen to get a good sighting, then identification is relatively easy.


The type of food being contaminated is a big clue as to the type of infestation. It also helps when deciding what tactics and bait to use when laying traps. In this section, we will look at the different diets of the brown rat and house mouse only, as these are by far the most prevalent species in Ireland.

House Mouse Diet and Feeding Habits

Mouse eating a piece of cheese.
Rat eating a piece of fruit.

Brown Rat Diet and Feeding Habits





Brown Rats

House Mice

Mice versus rats infographic.

If you believe you have a rodent infestation, then it is crucial to identify the species and take action to eradicate the problem as soon as possible.

Rats and mice are both prolific breeders, so time is of the essence. Contact us today for a fast, friendly, professional, and discrete solution to your infestation problem.

Identify your pest

By now, you should have enough information to identify whether your infestation is from rats or other rodents. This is critical when it comes to taking the right course of action.

Call in the pros

Rat infestations can quickly get out of hand. When you consider the risk to health and property, calling in professionals is the simplest and safest way to deal with an infestation.

If you are worried that you may have a rat infestation, call us immediately, our friendly and discrete professionals can easily and efficiently deal with any size of infestation. We have the right tools and expertise to quickly eradicate all rats from your property. We guarantee you will receive a personal service and advice every step of the way.