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What Does a Rat Look Like?

Rowan Burgess |

Finding evidence of pesky rodents like droppings is bad enough, but actually seeing a mouse or rat is unpleasant or frightening to many people.

Before you embark on rodent control, you'll need to know what you’re dealing with. It’s usually possible to tell the difference between mice and rats by their droppings and other activity.

However, seeing one in the flesh is the best form of identification. Let’s examine the key differences between a rat and a mouse.

How Do You Identify a Rat?

Rat Size

Rats are the biggest rodent you’re likely to see in the UK. They’re significantly larger than the different mice types and average around 15-27cm with a slender, elongated body.

Urban rats can be larger than their country cousins simply because of the easy availability of food.

If you want to get rid of rats, knowing what you’re dealing with is important, as rat traps are much larger than mice equivalents - plus, it impacts how much bait you’ll need.

Rat Colour

Only two rat species live in the UK: the brown rat and the black rat. However, black rats are very scarce.

Most common rats in the UK have fur, which is grey, brown, black, or a mixture of these colours, with the black colouring often described as melanic. If you see a black rat, it’s much more likely to be a melanic common rat than a black rat.

Mice tend to be a light or sandy brown, but they can also be light grey.

Rat Nesting Sites

Rats and mice have surprisingly different nesting requirements, so this is one easy way to identify which rodent you have if you find a nest. 

Rats favour nesting sites with good access to water and food, such as sewers. They can even drink up to 60ml of water daily! Because rats are cautious, they like their food and water sources to be within easy reach of the nest.

In contrast, mice prefer clean, dry, and quiet locations, so they're willing to nest almost anywhere.

Rat traps must be sited on the rat run from the nest, usually against buildings or fences.

How To Distinguish Between Rats and Mice

If you look closely enough, rats have several distinguishing physical characteristics that make them easy to tell apart from mice. Let's go over a few below.


Rat’s tails are unmistakable – they are thick, long, hairless, and scaly. Tails are one of the primary ways to distinguish rodents. Mice have long tails, but they are hair-covered.

Rat’s tails average 10-24cm long, depending on maturity. Brown rats have a shorter tail in proportion to their body, but other species can have a tail the length of their body, if not even longer. 

The key to distinguishing an immature rat from an adult mouse, both of which have long tails, is the absence of hair on the rat’s tail.


Rats have a slanted head, which is disproportionately large compared to the rest of their body. This can help separate an immature rat from a mouse.


Mice have more prominent ears relative to their head size and floppy ears, whereas rats have small, rounded ears. 

Facial Appearance

Rats have a blunter shape to their nose than mice. Mice have triangular snouts with long whiskers.


Like their heads, rats have large feet relative to their body size, particularly their hind feet.

Frequently Asked Questions

How Do You Know if It’s a Rat?

Physical identification is surprisingly easy if you get a chance to clap your eyes on your rodent visitors. A long, thick, hairless tail and large head confirm that what you’re looking at is a rat.

Droppings are another way to identify rodents; rat droppings are larger than mouse faeces with rounded ends.

Looking for Rodent Control? Shop Dalton Engineering!

You can’t ignore rodents as the problem will only multiply, and the specific problem with rats is that they carry some serious diseases transmitted via their urine and droppings.

If you’re looking for rodent control products, look no further than Dalton Engineering. We sell tried and tested bait and traps to deal with unwanted rats and mice.