Mice or Rats? Here’s How to Tell the Difference

Not sure if you’re dealing with mice or rats in your property? You’re not alone. Many auction buyers inherit uninvited guests, and knowing which pest you’re up against is key to solving the problem properly.

Here’s how to tell them apart:

Size and Appearance

Mice are small (7–10 cm), with large ears, pointed noses, and long, thin tails.

Rats are much larger (20–25 cm+), have thicker bodies, small ears, blunt snouts, and a short, scaly tail.

Sounds and Movement

Mice make light scratching or rustling noises, especially at night, often behind walls or ceilings.

Rats tend to make slower, louder thuds or gnawing sounds, often from basements or under decking.

Where You’re Seeing Activity

Mice prefer cosy, indoor spaces such as behind cookers, inside drawers, or in loft insulation.

Rats are more likely found under decking, along garden walls, or entering through damaged drains.

Entry Points and Damage

Mice can squeeze through gaps as small as 5 mm (roughly pencil-width).

Rats need larger holes (around 25 mm or a 10p coin) and will gnaw through wood, pipes, or brick to get in.

Why It Matters

• Treatment tools differ. Mouse traps won’t handle rats.

• Proofing methods vary based on how they enter and where they nest.

• Professional help may be needed if activity is frequent or extensive.

Takeaway: If you’re buying a property at auction, especially one that’s been empty, do a quick check for signs of pests. Correct ID means a quicker fix.